We have boat that came with trolling motor, boat not used in 5 years what should we do to service the motor/minn kota 40at before we put in water we hooked to battery it spun and quit?? not sure what to do we dont have manuel or any experience with trolling motors? need free advice please.

My guess is the motor has leaked water into the lower motor assy (behind the prop). and needs to be cleaned up and the brushes replaced.
here's a schematic:
Edge 40
You can try this to check for water leakage:-
1) disconnect from power supply
2) remove the prop
3) you will see 2 bolt heads behind where the prop was. Remove ONLY ONE of them for now.
4) if you see the bolt (it's about 8" long) is covered in what looks to be blask, oily/watery or rusty condition then you know that you'll need to overhaul it.
5) if it IS the motor assy, remove the other bolt and disassemble everything noting their location.
6) I would recommend replacing the brushes Part# 188-052 and the seal kit 2883460.