clutch problems

well i just bought this 89 rs camaro 5 speed 305 tbi
well when i got it the clutch never disengaged until alkmost all the way out and now its begining to diwsengage sooner
thats the good part
the bad part is at regular cruising sppeds if i depress the pedle without down shifting it slips horribly but if i downshift to the appropriate gear it doesnt slip a bit....
could there be air in the line and it just needs to be bled????
anybody able to give me a basic walkthrough of clutch replacement???
also should i even try and dissassemble and scuff the friction surfaces down and see if thats the problem the car doesnt chatter or anytthing whenm shifting not even when doing 55 in 5th and flooring it (which is one of the times that i was refering to for the slipping
also how do you bleed iot is it just like a brake where you depress the pedal and crack the valve allow fluid out close valve release pedal then repeat(duh brke bleeding) but any way first personal on hand clutch rplacement where im the one whos doing it helped but not doen one by myself and i was like 12 and 14 when i did it thwe first time and im 24 now so......

sorry so long and thanks in advance

well it takes almost the whole pedal now and all ive done is proper driving (ok harsh but proper driving ) i have to do the same to my brakes of my bonneville after my mom drives but she also starts to slow down (ie rides the brakes ) like about 200 yards (no lie) if she is doing 35 to 40 wow talk about riding the brakes...
but now my clutch is chattering a slight bit on engagement so it probably is smoked but i dont have the 112 for an oe and i want the 249 one and my 350 and that needs a carb so hopefully it hold up to the drags this friday(what are you retarded draging with a clutch like that lol) and yes slightly lol but yeah i got to cuz its stock now and im gonna mod the exhaust intake and pulleys this weekend so i gotta see stock times first then se how i makle out