If your Ai is only ever going to use a certian weapon or vehicle then I use the item attributes to attach him, I have assumed you know how to create waypoints.
From that screenshot you will see goto player and goto group, neither of these work in a multiplayer coop map.
You can use an event
Scroll down the 1st box to the ssn number of your Ai
scroll down the second box as above and select his wp list