Story Related and Unmissable
Before starting this DLC make sure all your equipment is fully repaired and you have plenty of ammo and health items. After you arrive at the Radio Tower you have to fight off some Raiders who have come kill the guy who sent the signal that brought you here. After wiping out the Raiders, Wernher will introduce himself and, after a brief conversation, he'll tell you to get yourself a Slave Outfit so you will blend in when you get to The Pitt.
Getting the Slave Outfit is easy as the nearby Slaver Camp is only lightly defended. Kill all the Slavers you see and loot the Slave Pen Key from one of the bodies. Open the pen, grab the outfit off the corpse that’s there and leave. After you get the outfit, Wernher will appear so talk to him and go into the Tunnel but make sure you tell your Companion(s) to wait as they are not allowed in The Pitt. Once you are ready, talk to Wernher and press on the nearby Handcart to go to The Pitt.
After arriving, Wernher will have an argument with some Slavers and kill them. Once the Slavers are dead follow Wernher to a gate to the North East of your position where he'll say he can’t go any further. On reaching the gate, Wernher will give you your orders to find a lady called Midea and will also give you a weapon if you ask him nicely. The bridge ahead is dangerous as there are loads of mines, traps, dogs and possibly also a sniper on one of the cable support pylons. If you have the Light Step perk then this section shouldn't be hard. After crossing the bridge you will come to the entrance to Downtown.
Before you can enter Downtown, you will have to un-equip whatever armour you're wearing and equip the Slave Outfit. On trying to pass through the Security Gate you will be stopped by a Slaver called Mex, who will confiscate everything except your Slave Outfit and your hidden weapon (if Wernher gave you one). After being stripped of everything walk through the door.
The trophy will pop once you’ve entered Downtown, your hidden weapon has been auto-equipped and the local Radio Station has been detected.