3) Reach extraction point
This is going to be the final and the most difficult objective of this mission. You will have to reach the extraction zone which is located near the church, to the south of your current position (#1). There's only one road leading there, so you can't get lost. Check the second screen (#2) if you want to find out where you'll have to go. You won't encounter any hostiles right away, however I wouldn't recommend moving too fast.
Take a closer look at the first screen (#1), because that's where you'll probably encounter your first opponent (#1). I think it's fairly obvious that you should try and eliminate him from a large distance, so he won't have any chances of performing a successful counter-attack. Keep heading east. The rest of the team should be following you, but try maintaining a larger distance from your colleagues. You will encounter your first sniper just around the corner (#2). Thankfully, it's going to be very easy to locate him.
You may proceed to the next section. Make sure that you're not moving too fast. The second sniper will be to the north (#1). Once he's gone, go there with rest of the team. You will encounter two additional hostiles just around the corner (#2). Kill them.
Try making a few steps forward. The third opponent will appear to your left (#1). You will have to kill him, however he may also hide. If he does that, you would have to throw a grenade at him. Hide behind the plant. Try taking out at least one enemy soldier from here (#2). The second group MAY appear to your right. If you don't see anyone, you will have to be more careful while trying to secure this area.
Don't head on to the extraction zone right away, because the area is not safe. Try hiding near one of the buildings to your left (#1). You should be able to take out a single enemy sniper from here (#2). You must do this quickly, before he sees you.
Now you may allow the rest of the team to enter this area. Send one of your colleagues to hide behind the sandbags (#1). It should be your sniper, because he'll have a chance of spotting other enemy units. Once the area is clear, start moving forward. You should consider hiding behind one of the building which are located to your left (#2).
Turn right. You will probably notice at least one additional opponent near the crossroads (#1). You will have to take care of this small problem. You should be able to surprise him. Once he's dead, head on to a small platform which should be located to your left (#2). This will allow you to have a much better view at this area.
The final group should be hiding BENEATH your current position (#1). As a result, you must be very careful, so you won't lose any health points. Once all the enemies are gone, gather the rest of the team around you and start moving towards the designated extraction zone (#2). You shouldn't encounter any additional hostiles for the time being.