1990 s13 hatch help

need some work done to my 1990 s13 and wondered if anyone could help me …i need to putt in a new upper control arm have no idea how to do it …i need two tiny holes in the drivers frame rail patched and i need to either fix my quarter pannel or find a new one (holes rotted thru)

3 things.

1: rear upper control arms? (RUCA’S) (i sure hope, cause if you say front, your mech is taking you for a ride)
2: are these rust holes or factory holes?
3: how badly rotten is the rear 1/4? beyond repair?