My guess is you are in Move mode when attempting to place the units on the map.
Once you have selected the unit you wish to place on the map you need to make sure the Move/Place Mode button is depressed (the one on the left with the + sign)
If you want to make this a reinforcement you'll want to place it on the edge of the map where you plan to have it arrive otherwise place it where you want it on the map.
To place the unit on the map you click the right mouse button in the hex you want to put the unit in. When you place an officer or a unit on the map it disappears from the Unit Dialog box. Unlike regular units Supply Wagons are unlimited so to place additional ones just keep right clicking until you have as many as you want.
To move a unit you toggle the Move/Place button so it isn't depressed. Then you select the unit just like in a game by clicking on the unit box when you right click on the map the unit will move to that new location.
There is an introduction to the scenario editor at the ACWGC Engineering site
http://www.acwgc.org/ACWCO_Engineering/
I hope to add more info on using the editor to the site when time allows.
Gen. Ken Miller
1/2/VI
AoS
