You need to procure a shop service manual for the bike.
It will improve your chances of getting it running by about 98%

 

Can barely get it to roll. Rear wheel is not completely locked up, but very difficult to turn.

Crudded up rear brake? Rusted solid drive chain?

Clutch has zero tension

Hydraulics crudded up? If not hydraulic then broken or unhooked cable?

it is stuck in neutral

Crudded up shift linkage?

S F

 

If clutch simply has no pressure when working lever could be as simple as clutch way out of adjustment. Which of course would make bike very hard to shift or not shift at all.

 

You got your work cut out for you for a first time owner Good luck.

 

It sounds super entertaining for those who are passionate about this. -...it is over 30 years old. ...usually they need a lot of refreshing, or a downright restoration. .that is the way it goes. unless you consider working on these old relic PART OF THE FUN.... your would be better off getting a much newer motorcycle that is ready to ride..