Place bucket under explosive, attach bucket to balloon with rope. Place 2 balloons under (right) balloon, 1 on left 1 on right on their side and secure together with rope. 2 balloons will support the first one making 3 balloons to raise bucket with TNT. Attach last bucket to balloon on left with rope.
Connect up battery and electric motor to operate fan. Lastly place blowtorches one above the other with a good gap, above collection area. So that top blowtorch will pop balloon at the same time the lower blowtorch will ignite the TNT. You will need to use trial and error to place the blowtorches in exactly the right place. Good Luck