Watch how to use a Torch when installing a rubber roofing membrane. There are other techniques but this is just one way.
Other videos on Torch Down:
https://www.youtube.com/watch?v=t2_snJQfJYI
https://www.youtube.com/watch?v=4V1eri1k_cE&t=206
0:00 Basic principles of Torch Down
0:14 Firestone APP 180 is used
0:35 Roll out entire roll before Torching
1:00 Roll up half of roll
2:00 Showing how to use Torch
4:00 Assistant is getting another half ready
5:00 Kicking roll with the foot while torching
5:50 Teaching howto torch at end of the roll
9:00 Tuck membrane under flashing