Scourge of War Boards

I would like to clarify the choosing of a specific target for artillery. Do you point and click on the red cross hairs above the unit or it's flag. It appears that when you point and click on the cross hairs, the aiming icon changes back to the bayonet. I assume this means that you have chosen that unit as the target? Thanks.

I play with couriers, heres how it works for me , select arty commander, click target unit buttom, courier goes out, when arty commander get order the curser changes to gold triangle, then click on target units flag, curser changes back to bayonet, done.

Hope this helps.