Hi there and welcome to the forum. PLENTY of people around in here that have taken these old bikes apart and together that it can be done in thier sleep......lol
Ya, pull them side covers, and be VERY careful, because the tabs that hold those covers in place tend to be a mite brittle after 30 years and WILL break off. Don't ask me how I know this.
After checking the oil (left side.that black plastic looking thing with the finger tab forward of the left foot peg), I would pull the spark plugs caps (carefully), remove both plugs,
hook up jumper cables to a non running cars' battery,or, a battery charger, turn the key on and see if she lites up, make sure is in neutrel, pull the clutch handle in and hit the start button JUST long enough to see if the motor spins.
NEXT, put the plugs back in, and pull the the air cleaner and squirt about 2 er 3 seconds of starting fluid in the air box, and see if the motor will fire (direct the spray towards
the front of the bike).
IF she coughs er sputters.thaz a GOOD thing.....you may JUST have a runner on yer hands, and you've earned yerself a beverage of your choice........lol
THEN, ya can commence to pulling the seat off (12mm btw), being careful not to lose the spacers that are on the bolts.
The gas tank is also 12mm which just now appeared after you removed the seat. Depending on how big your hands are, or how dexterious you are with big fingers in tight places, you'll need to pull the vacuum line and another little line (breather line I THINK is what it's called), and then the fuel line to the carberators.
THEN, take off the fuel tank bolt, and for this next step you may or may not wanna don a pair of gloves. Because you are about to disrupt someones happy home for the
last 15 years, and lift UP on the back of the tank, being careful not to rip those 2 rubber flaps off the frame, putting your other hand in the curve of the tank by the triple tree,
and pull back...........Good Luck!!