I took my new 2016 Novara - Safari out for it's first ride today, and upon returning I heard an intermittent spoke hitting sound. I suspected that one or more spokes were contacting the front disc brake caliper, and that's exactly what it is. I flicked each spoke and found some of considerably lower tone/tension than others. The offending spoke being one of them.

The rims on my bike are "Alex ATD 470".

Now here's my question, and I am new to all of this. My assumption is that all I need to do at this point is get a spoke adjustment tool, and tighten the looser spokes up to the same tone of the tighter ones, and that will likely take care of the issue. Is that the case? Also, is there a specific level of tension or tone I should be setting as a target for my specific rim? I understand that I would have to purchase a fairly expensive spoke-tension measuring tool to find out what the current tensions are, and then set them all to whatever the specified tension may be. I'd much prefer to skip the expensive tool purchase if possible at this point, and just do what I said previously about bringing the lower toned spokes up to match the higher ones.

That's a warranty issue you have there, if the spokes are that loose. Sounds like the wheels weren't built properly in the first place if the spoke tensions aren't even, most likely because they were machine built. Take it back and get the shop to stress relieve, re-tension and re-true the wheels. If you simply tighten the loose spokes you'll likely pull the wheel out of true.

OK, so then it sounds like they weren't set properly to begin with. I'll make an appointment with their certified tech there and hope for the best, thanks Trevtassie.

While you're correct in general theory, it's a bit more complicated than that IRL.
All parts of a wheel interact. If a wheel is true at uneven spoke tension, then bringing ALL spokes to the same (high) tension will bring it out of true.
To keep/create an evenly tensioned and true wheel you might need to slacken the taut spokes as you tighten the slack spokes.

+1
If you have no experience truing wheels, best to let the warranty cover it.
You don't want to take in a wheel that you have all out of whack because you tried unsuccessfully. It kind of makes for "hard feelings".
IF it were an old beater wheel, I'd have a somewhat different opinion.

I always suggest to my customers that are interested in learning about true/tensioning wheels to start with one the aren't using. There are plenty of wheels on the curbs for free in most communities on trash days.

I agree with both the suggestion to let the selling shop handle this wheel as well as that the prior to "fixing" trueness of the rim is a BIG indicator to after tensioning results. Wheels are a system in a state of balances. Not understanding this give and take of tensions WRT rim condition when no tension is present is a path to future issues. Andy

Thanks for all the info and advice. The actual bike tech was at REI today, so I brought the bike down and he took care of it. Since I much prefer doing all of my own mechanical work, I'll take Andrew R Stewart 's advice and find some unwanted rims somewhere, and then do what I can to learn the craft.

Good!
When you do-
Get a GOOD spoke wrench. The "one size fits all" will spread open on a tight nipple. After that, it tends to round off nipples because thew slot has become tapered instead of "square".
Don't get too bad of a basket case wheel. They'll drive competent wheel builders to wits end.
Frozen/tight nipples can strip and at the best still provide a poor sense of feel. You can be rounding a nipple on a loose spoke. Tight, but no tension.

You might actually be better off buying one of those $30-35 replacement wheels that actually would fit your bike. That way you could have a usable "spare".
New spokes & nipples, and a good sense of feel when turning the spoke wrench.
It'd probably save you that much $ in frustration.

More great advice, thanks!

OK, so I'll need a spoke wrench of course, which I've ordered, but I'll also need a rim-stand to work on the rim and spin it to test as I go. Now what about proper tensioning? Are there specific specs for specific rims and types of usage, along with a spoke tension measuring tool? Is there also a tool to verify the trueness of the rim?

Tension Meter such as PARK TM-1
Truing Stand. various brands.

Spokes tend to have specific tension "ranges", depending on gauge, use and various other factors. (and probably more arguments about what's best)
DS spokes on a rear wheel will have higher tension then the NDS spokes. (DS= Drive Side)

There's lots of tutorials if you use your search engine. Some very good and some not. Compare a couple different ones and you can kind of filter out the baloney.

You actually need very little after a good spoke wrench. A stand is nice, but you can hang the bike by its seat and use the brake blocks just as well. I raced on wheels I built that way. Many advocate getting very expensive Park and the like stands. They pay their way IF your time is worth money and you build a lot of wheels. I've been using a $30 stand and an $8 dishing tool for 30 years and have ridden virtually every mile on wheels off that stand.

To use the bike itself as a truing stand. loosen the brake bolt a little and rotate the caliper so that the shoe is almost touching the rim. Stand right in front or back of the bike so you can see that gap, then adjust the spokes to make that gap constant, gradually moving the rim until it just touches as you spin the wheel a full circle. For roundness, tape or rubber band a pencil to the forks or seatstays in similar manner. These principal are exactly what the best stands do. They just make the setting up faster.

Ben

You will find this very helpful. Wheelbuilding

While this, in essence, will help to obtain a true wheel, it will not, in all probability, help you obtain proper, UNIFORM spoke tension which is necessary for the long-term good health of the wheel. If you have the ear for it and can achieve a true and round wheel and have all spokes at the same and proper musical pitch, then have at it. Otherwise, it is a job best left to the shop. However, as your bike is new, I question whether the selling shop had properly tensioned the wheels to begin with. They may not posses the skill set required to do that now. You may have to seek out a qualified LBS.

Bike has disc brakes.

Your method works on GOOD wheels.
IF one is dealing with "beater" wheels that may be "wallowed out" from hitting curbs etc. one can quickly spiral down a rat hole of making it worse as you try to make it better. That happened to me at my very first truing attempt.
I had a "high spot" I "pulled down". I didn't realize that I had a "high spot" exactly opposite that I made worse.
Start on the other side and I have this real bad "high spot" It didn't take too many back & forth attempts when I had the worst hop....
A 2 finger stand detects this readily and shows how much each side is out at the same time. (they don't always hit curbs straight on)

Now when I deal with an "unknown" rim, I use an adjustable wrench as a crude gauge and run it around the rim looking for "bad" variances. It gives you an idea of what you are facing.

Got an REI Bike [X], check when the store has some Bike Repair, hands on, Classes.

My experience with REI has been absolutely abysmal. If I wouldn't have gotten such a great deal on this bike, I would have gone elsewhere. I doubt I will by another bike from them. They don't really care about proper bike preparation or service, and hence their customers. I would not recommend that anyone purchase I bike from them unless they already budget out paying a trusted shop to do the initial set up and then rechecks and maintenance later on. Either that the person purchasing has to be able to handle all of this themselves. I'm working on getting myself to where I can do that later.

Truing wheels isn't rocket science. Turn bike upside down. Put on some leather gloves. Grab pairs of spokes that connect to same side of wheel and squeeze each pair on both sides while rotating wheel. If any pairs are really loose then tighten them up a little. If you're trying to straighten a wobble then always loosen the pair of spokes opposite from the spokes you tighten. Never turn a spoke nipple more than one full rotation at a time. Use patience & it's easy to get good results.

Thanks for the tips there.