At the start of the mission you will be tasked to mark locations with smoke. The building right in front of where you spawn is a building surrounded by some tents. Inside are the allied troops and they appear as blue dots on your map. Simply walk over there.
Despite this being a stealth mission its actually way easier to go guns blazing. Triggering an alarm doesnt fail the mission and when you do trigger one enemies in the area rush to you and are easily killable if youre behind cover.