Go into Forge with at least two people and find out who is host (the best way to create the game with one person and have him or her invite the other player in; the person who was in first is definitely the host). If you only have two people, get the host into the tube using the "Turret" glitch. To do this, create a turret next to the tube, turn into a Spartan, go on the turret, and turn it all one way. Then, transform into a Monitor. Basically you will need a non-host player outside the tube. The non-host player on the outside of the tube should create a receiver node and change it to a channel that is not being used. Take it to the top of the tube and get it into the little gap as far as you can. Repeatedly tap A (picking up and letting go). It should half fall into the tube. When this happens, the player on the inside needs to grasp it and position it so it does not hit a wall (otherwise the teleporter will be blocked). The player on the outside should now create a sender none and put it into the same channel. Try to step through. If it says that it is blocked, get the player on the inside to move it. If you go through, the glitch has worked.