#1. Fight your way through both xenomorph and PMC forces. When you reach the path that turns towards the left and you clearly see the upper part of the derelict alien ship ahead, turn to the right and enter the building. Look for a dog tag on top of supply cache by the wall to the right.
#2. Go up using the elevator and clear the hallways until you find the “maker's” remains. Go around it and check the floor at the end of the catwalk to the right, near the remains. You'll find the mission's second dog tag there.
3. After exiting the derelict ship, kill the xenos and PMCs along the way and continue forth. Once you see the path branch to the left, follow it first and head towards the lift. You'll find the last dog tag on a crate beside the lift.