Cove Valley Village
At the beginning of this level you will see a group of rebels in front of you being pinned down by guards. You can choose to save the rebels from their execution by silently taking out the guards with your Mk 22 (you have to be quick to avoid giving away your position) or there is a hill to the left of you where you can crawl down and sneak around the back of the houses and around the guards.
Stop at the end of the first house and look around the corner with the camera. Wait for the guard to walk away and then quietly proceed to the end of the second house. When at the second house, check around the corner with the camera and wait for the guard to walk away then crawl into the grass. Run around the small cabins and follow the path. When you reach the end of the path take out the guard silently with the MK.22. On your left there is a route which you continue to proceed.
==Cove Valley Village (Hill) Stick to the wall and shadows as this will keep you hidden. You should see a guard along the way that you can't miss, so stay crouched and either take him out or silently proceed. As you proceed, on your left there should be a little ledge you can jump up on by pressing triangle. There is a couple of more ledges to jump up on, so continue to do so while keeping an eye out for patrolling guards and taking them out if necessary. When you have finished climbing up all the ledges you can proceed on to the next area but before you do you will get a call from Colonel Cambell and Rosemary, so listen to that.