I will just give the command on here so you can do it if you want without watching the video:
(The video dives more in depth on how to do it though)
/summon Creeper ~ ~ ~ {ExplosionRadius:127,Fuse:1,ignited:1}
Remember- The ~ in the command is where you want to put the coordinates of the place you want the explosion at. You can also experiment with the "Radius" input and make it bigger or smaller, 127 is the max you can go.
