How to make a trunk in Asterisk 13 FreePBX to call to other SIP networks, a voip peering?

Is it just me, or there is not enough references one can dig up, as to what context to use when setting up a trunk under FreePBX...? https://www.google.com/#q=freepbx+context+description lands no FreePBX wiki page ... at least not on first page of results anyway...