Here is the route you are going to take:
If you fail, you will respawn by the big circle in the fields. From there you are going to follow the red line until you get to the lookout tower where my character is located.
 
From there, climb up when the guard is not looking, preferably when he is to your right. If you can and want to, throw a diversion lure to make him walk away. Then, sprint to the left and hide behind the building.
 
Now, you are going to run until you get to the guard post on the left side.
Jump across, and run until you are where I am on the right picture above.
 
Now, run up to the building closest to you, and stay out of sight.
 
On the screenshot where the route was shown, there were two smaller red circles next to the big one. Each small circle shows where a door is, and you can choose which one you want to enter the building through. I chose the one on the left, which is the one below the big circle on the map.
 
There might be a guard inside, so wait for him to leave. Then, walk up the stairs and you will meet Sam Fisher.

Unfortunately, you have just completed the easiest part of this mission. Now, you have to defend the building until Sam is done hacking. I can't really guide you through this part of the mission as it will most likely be different every time.
All I can do is to recommend you to use your grenades and mines as much as possible, as well as your rebel skills whenever you are able to. This will help out a lot. It will also be much easier if you have the grenade launcher attachment for your gun, and the Desert Tech HTI BDC sniper, because these two things can one-shot any vehicle.

Also, take out the alarm located south of the building.

I really hope you were able to at least get to Sam Fisher using this guide, and hopefully you can defend the building too! Good luck!

Check out my review of Ghost Recon Wildlands here!

https://steamproxy.net/sharedfiles/filedetails/?id=2370120676