To start i have minimum car audio knowledge.
I bought a 1998 ranger a while back and it was/is all set for subs/amp (at least i think :P)

what im looking for is mainly a correct diagram of what all need s to plug into amp, then into sub
and any other info that can be given

What i have:
truck has a pioneer deck and door speakers
and i bought from a buddy: comp vr12 sub and kenwwod amp

wires that are wired to the back already:
red wire: power
black/silver: rca?
ground
and a blue wire: speakers?

so main questions i guess is em i missing anything?
what kinda wiring do i need to go from amp to sub?
how do i make sure im not over working amp/sub?

The blue wire is your turn on lead to turn the amp on when the head unit comes on. Speaker wire goes from the amp to the sub, 16 gauge is fine.

should there only be on end on the blue wire?
or should there be 2 (+/-)?

im only finding 1

Just one. It goes into the remote slot on your amp and the other end gets crimped/soldered to the blue/bluewhite wires in your head unit wiring kit.

had a buddy do it
all was good just had to plug it all in and get a new fuse for the power cable