How do I reset my Security System

[Kidmexicali]

I just bought a 1991 sport trac and the alarm system (security system) does not function the doors have numbered buttons on the door how is this used? also would like to know where online I can download an owners manual and repair guide? thanks if the question sounds simple its because I know nothing of this vehicle me being former chevy entusiast now I would appreciate any help Thank you from a new member

 

[RangerX]

Sport trac, or sport? Sport tracs first year was 2001.