Very self explanatory as you just need to buy all skills for ANY of your skill branches. TIP: If you do the drone skill branch first, you will get TWO achievements ;)
For this to happen though, you're going to need a lot of resources for upgrading. Here is a video I made of the two spots I have used AFTER patch v2.0 came out for farming resources.
This video explains the method very thoroughly but in case you missed it, here is the basics:
What you need:
- frag grenades
- EMP drone unlocked
Basically, EMP the convoy as it drives by. When it is stopped, throw a grenade at any enemy hummer that is out of the blast range of the resource truck. Next, take out the driver of the truck - this is very important as the EMP only lasts shortly and the truck can drive away if the driver is not neutralized. MAKE SURE TO KILLS ALL ENEMIES BEFORE TAGGING THE TRUCK. This works on the basis that you can fast travel the second after you tag a truck while the green text is on the screen. So once you tag, immediately hit the back button and fast travel to the specified areas in the video.
The reason I have two areas: sometimes you mess up and the truck will not respawn for 30 min. No worries, just use the second location :)
Happy hunting! Let me know if there is any questions or clarification needed!