I'm new.. and I have a problem, with shifting/derailleur

[tsume]

I decided to take up biking with a friend to try and lose some weight and just ride around the city, now I'm pretty positive its a road bike, Its a cheap brand I know that, a Magna great divide something goofy like that, now I've had this bike for years, but I've never used it, my aunt passed it on down to me, the bike is a 15 speed i believe but on the gears the chain would only switch between the 2nd and 3rd gear counting from small to big here, no matter what my shifter said, 1-5 now this was frustrating trying to bike up a hill when my legs are exploding from within but it was fine turned out to be fun on the ride down, now i came home and got some tools and started destroying the bike pretty much, but not really, i made sure the derailleur was lined up with the last sprocket for the low gear limit, so i tried the shifting and it still wouldnt work, the derailleur doesnt seem to be bent or anything. so I'm assuming its a problem with the cabling? also on the shifter knob(its a twist shifter) its extremely difficult to twist to gear 1, im assuming this is a sign of a problem, now the end of the shift cable is frayed i believe thats what its called, and i took the wire off the derailleur completely then put it back the way it was pulled as tight as i could and pinched it with the nut, now i started messing with the adjuster nut, from some video i saw on youtube and actually got the chain to jump up to the second gear, BUT it took the tightened screw too be completely unscrewed, the adjuster screw that is.. I'm sorry, I know I'm extremely bad at explaining things and I know this is long -___- but I would really like to get this bike working, since then i completely removed the wire except from the actual shifter because idk how

the shifter is a dynagrip twist shift with the model number ML-G22-5 if that helps anyone.....this is a lot, so i understand if no one replies ;f

[panamapete]

if the cable is frayed, change it out or bring it to a bike shop where they will do and set it back up. also make sure the teeth on the cogs are straight and not bent. it may be an issue. if i was you i would start changing out cables, and lubing things up. there could be multiple issues but we've got to start somewhere, so start with new cables if the old ones are damaged. one more thing you may have set the tension too high on the rear derailler cable and it needs some more slack, keep playing with it and watching youtube videos, you'll get it. and start learning names of things, we can help much more when we know exactly what youre talking about.

[Homebrew01]

Go here:

http://www.parktool.com/blog/repair-help

Maybe that will help you get started.

[CbadRider]

Moved from Road to Mechanics.

[RubberLegs]

Just something to keep in mind. This IS a $100 entry level Target bike. So if anything major needs replacement, it may be a better investment to look at a NEW one instead. All the components are low end, I know, I have a Magna Great Divide in the back of the garage! It is a solid bike, good tool to learn maintenance on, but it is frustrating when things don't stay in tune and need constant tinkering...it IS the nature of the beast.