This is in an online infiltration mode, where you can build your own base (FOB) and infiltrate others' FOBs. When you've infiltrated someone's base, you'll get this trophy.
Online FOBs unlock after mission 22, which is basically a tutorial for this mode.
After this, FOBs will appear under the Mission tab on your iDroid. In here, select someone you want to infiltrate. When the infiltration starts, you should already get the trophy, so win or loss doesn't matter (I failed my infiltration, but still got the trophy already).