You MUST overwrite activities.ini and index.ini in base for this mod to work. Simply copy "activities.ini" and "index.ini" provided with the mod and paste it into "base.rte". 
When it asks if you want to replace it, say yes.

If you don't place the brainbunker at the start of the game you can use a zombie instead. Go to brains and select the zombie named "braincase".
This will mean that all the enemies follow you and if he dies, you lose.

Tutorial over, enjoy the mod!

_blipflip.