How to get on top of the level foundry

First spawn a teleporter at the ground now go to the ceiling and look for an open window like place in the roof. when you find it put a spawn a teleporter and try and make it stay on the bar on the roof you'll know what i mean when you see it. Once you get it go down to the one you put on the floor and go through it but don't forget to crouch while going through or you will die.