There is a cutscene at the beginning that sets up the mission, where you are contracted to help in an assassination. Once you finally gain control, follow Asha until you get to a guard with his back turned. Sneak up behind him and do a stealth kill, then take out any other guards in the room.
Asha will open the door and once it's open, go to town on all of the terrorists in the room, using the explosive barrels to help if needed. When it's clear, follow the path using the markers, killing anyone in the way, until you are stopped by a big explosion. After the smoke clears, Pierce will open up a new path for you.
Go through this room and the group will split, with you going with Shaundi, while the other two go a separate way. Open the door with the marker and follow the path into a room with chemicals and explosives. Kill all of the enemies you find, including some on the upper level that have sniper rifles.
Find the stairs and go up to the second level, then go through the door. Meet up with Pierce and breach the door, killing the enemies that are marked. Clean up any remaining enemies and chase after Cyrus. Once you open the door, you will get ambushed, but Asha saves your butt.
Continue chasing after Cyrus and when you get to the second marker, a cutscene will play out with some Quick-Time Events mixed in. When it's over, sprint to the missile silo and you will grab onto the actual missile. Climb up the missile and press the designated buttons as they appear on your screen. Once you jump off the missile, the mission will be over.
