I would suggest getting yourself the Clymer manual. Although several very specific specs are incorrect or missing, there are many instances when I found the directions easier to understand than the FSM, especially when I was new to wrenching.
To adjust your clutch...remove the chrome cover to the clutch, back off the adjusters at the clutch lever and the clutch housing, loosen the locknut on the clutch actuator at the engine end of the cable, turn the adjuster screw in until firm resistance is felt(don't get confused by a stuck or corroded screw, get it to turn relatively freely in and out, then go in until resistance is felt), back off the adjuster one quarter turn from the point of resistance, hold the adjuster in this position while you tighten the locknut, retention the cable starting with the adjuster on the engine, finer adjustments can be made now at any time at the handlebar clutch lever.
As mentioned earlier, your clutch plates are probably stuck from sitting around. They will usually unstick if you can get the bike moving in gear so that fresh oil can get to them. Start the bike in neutral, get it rolling about 5mph, give it a little gas, pull in the clutch, then firmly shift it down into first...... or try from a standstill, in neutral raise the engine speed to about 2000-2500 rpm, pull in the clutch, and try to firmly shift into first. It may take several trys.
