I figured it out from examining one of my old missions.
First, there are two menus in the ME that need to be addressed. The "set rules for trigger" menu, and the "airplane group" menu. The first thing to do is select the airplane group you want to act on by selecting it on the map, then the "airplane group" information comes up. Select "uncontrolled" but, don't change the start time. Then select the "action triggers" button (the one with the vertical yellow line)>"add" button>"perform command">"start." You can name it anything you want.
Then, select "set rules for trigger" button. You see three boxes, "triggers," "conditions," "action." In "triggers," select, "once," "no event." In "conditions," select "more time," and how many seconds you want before start. In "actions," pick "AI task push," then pick the unit you want. Do this for each unit you want.
It appears that the MIDS LVT being ON is required for the TCN to work. It is documented in the User Guide. Perhaps people need to be referred to User Guide before reporting an error... Mystery solved as User Error!
mytai01's post in I want my AI unit to sit quietly till activated. was marked as the answer