The simlest advice you can get is to simply read the name of the kit:
First
Aid
Kit
"First Aid" does not imply healing anyone, just giving aid. Your kit should center around; cleaning wounds (and keeping them clean), stopping bleeding, and imobilizing fractures.
SAM splint
Gauze pads
Tape
Betadine/alcohol/peroxide
20ft basic rope
Maybe some bandaids
Water will already be in your pack.
Add in a sharp knife, som scissors, and tweasers to pull material out of wornds, and you'll be equipped to prep some one for transport.
That's all winderness first aid is intended to do; get the victim into a state in which they can be transported, or move on their own.
Warning: Note that I don't bring pain killers, don't get hurt around me because I won't care how much you hurt.