The valves by the intake manifold (that's the carb side) are intake valves and the ones to the opposite side (exhaust manifold) are the exhaust valves. The spec is 0.012" that's right. Have someone start the engine and take note of which way it rotates, then spin it that way with your wrench. You could use another pulley if you can't reach the crank pulley but I wouldn't recommend it much, I was used the alternator pulley to do this job. Alternatively you can jack up on of the rear tires, put it in 5th gear and spin that tire by hand, would be a lot easier if someone would spin that for you while you adjust the valves tho.
The way to see if piston #1 is at TDC: Remove the distributor cap and spin the engine until the rotor is just about pointing at #1 spark wire, then look at the markings at the passenger side crank pulley, there are some numbers there and a mark on the crank pulley itself, it goes 20 10 and 0. Spin the engine until that mark is at 0. You're now at TDC. Another way is that both exhaust and intake valves are closed for #1 at TDC.
First go for a drive (at least 15 mins) to really warm things up, including the oil cause if you warm it up at idle then the only thing at adequate temp is the coolant temp.
Then shut the engine off, remove everything in the way, loosen the valve cover fasteners a bit and then start the engine again let it run for like a minute or two. Shut it off again and remove the valve cover completely. Do the adjustment and double check to see if you've done it right and tightened the locking nuts enough. Then put the valve cover back on and use two fasteners to just secure it into place, DO NOT TIGHTEN THEM. It will prevent engine vibrations from throwing the cover off and the oil pressure at idle is so low the it won't leak from the sides and make a mess. Start the engine and let it run for a minute then take the cover off and recheck the clearance. After you're done, replace the cover gasket and install it regularly this time. This is an extra step I always do to make sure it didn't cool off much during adjustment to throw off my clearance and also to double check.
And remember: ALWAYS set the lash on the loose side and not on the tight side, but no so loose that a bigger feeler blade could slip through easily.