Instruction for installing rc to LEGO unimog
I found this utoob video as the first hit for a search using "install pf lego unimog" and also this thread on EuroBricks Which recommends a different video. So instructions are definitely out there.

I think you'd be better off trying it yourself. Don't be intimidated by the size or complexity of the unimog, have a go. Worst case you'll have to reassemble it using the TLG instructions and then try some of the online instructions.