1970 Chevy Chevelle door locks

I have been workin on my father in law 70 chevelle.I cannot figure out how to fix his doorlocks?Inside handle assy works but outside handle button doesnt work and pass side is really hard to push and have too burry button and pull so this side is going to break too?I see a shaft that slips off the 90 degree lever. Is that suppose too be secure to the lever or is the shaft to be straight?And how do you change out without pulling the steel inner skin off? Thanks bill