Right then you need to place a trigger (F3) around the area you want the base to be, change the size to suit. Set the condition of the tigger to 'not present' and then set it too west or east on who tiggers it. So when fo example all the russians die it will trigger. As for the end you need to select 'End1' , thats in the middle of the trigger options box, also do check out the ed department especialy macgubas tutorial mission as this covers all the basics and you can learn from there. Happy mission making.
GI-YO