As a rule when buying used, disassemble, lube and properly adjust the bearings/cups on the bike. You'd be surprised to see the condition of the unseen places that are critical to the bike's performance and reliability.

Just as a starting point, pull the wheels and slowly turn the axle/spindles with your fingers to feel for play/looseness and sticky rotation. If it doesnt feel like satin, do that one first.

Can a noob do this? Sure, if you arent intimidated. Just get yourself a set of cone wrenches (inexpensive) and a can of bearing grease....though the purist may shout me down for using a thick grease and find an instructional video on youtube.