Gears of War/Act One: Ashes

Lure The Berserker Outside
Here is where you first encounter a Berzerker. You must lure it outside so you can use the Hammer of Dawn on her.

You will travel room to room with the Berzerker chasing after you. Lure her towards the doors and she will bust through them.

Kill The Berserker
Once you are outside, use the Hammer of Dawn on her twice to finish the job.

Congrats, you have finished Act 1!