OK, will do in the future. I did get them to fire. They're the three German mortar units in the tutorial.
I wound up simply firing them at the pre-setup target points since in two of the cases that's where the Russians were, or were heading. Seemed effective.
Still trying to work through the intricacies of interface, how things work, etc in the game, and also why I keep getting my rear end handed to me on a plate (although the later, I suspect, has something to do with my poor tactics).
Not using smoke and cover effectively.
Thanks for the help. I'll try some more practice games to get the hang of it.