88 non turbo idle problem (new)

[88SupraQ]

I just bought an 88 non turbo and have already fallen in love. The guy I bought it from said he put an r158 tranny in along with a new clutch. When I was test driving it it ran perfectly and shifted real nice, but being a dumb 19 year old I jumped on it on my way home. Now she still idles in neutral fine, but when a push in the clutch and put it in gear she starts to idle real rough and lunges forward if I'm not stepping on the break. It is also abnormally hard to put in gear and shift, and down shifting is damn near impossible. Could this be because the clutch is not engaging all the way? I'm not real good with cars so I really would appreciate any help!!

Also, does anyone know where I could get the manual? I can't seem to track one down

Thank you in advance!!