How do I use ammo trucks?

[Charles22]

Imp: No that's what I meant, you call only change it in prefs before the mission is given to you. It's possible you would therefore pick the map size to the incorrect mission type therefore. You would have to keep doing that until you randomly got the correct combination.

As far as loading one, what does that involve? IOW, do I have do to do things like pick AI forces and place them (not something I want to do)?