There should be a wall to your left or to your right with crates on top of it.
If it is on your left go to the far left corner and when the wall is on your right just go to the right corner right by you.
Now "hammer jump" onto the gap between the forged wall and the map wall and keep jumping.
Then hit the hammer against the map wall to get you ontop of the forged wall.
Do not go through the hole or you will have to start over. Slowly inch your way left to the playing field but dont get off.
Now jump up on to the higher portion of the wall. Next just hit all the crates off and get the bomb carrier to get to the gap,.
Jump up and drop the bomb while you are right on the edge so you can catch it and then watch as the other team tries to get up.
If you want help with the glitch send a friend request to me, Helavor.