Please post more detail what you are after or else you will rpobably not get what you are after. . .
Q1. Try using the "Unit - Order [Your unit to move] to Move To [Location of where to move to]" action since using that you can issue the move order and thus your question is answered.
Q2. Get the trigger to trigger with "Unit - A unit enters [Region you want to have unit enter]" then after your actions are done use "Trigger - Turn off (This trigger)" to switch the trigger off (can be turned on if you want it to by using the opposit action) or use the custom script action "call DestroyTrigger(GetTriggeringTrigger())" if you want the trigger to perminatly be turned off (NO WAY TO UNDO)
Hope this helps you. . .