Much like Half Guard and Side Control, the first thing you want to do is pummel for the underhook. This will allow you to ramp your opponent towards you setting up for the farside armbar. Take your free hand and place it directly behind your opponents head on the mat. Once based, spin around to the opposite side. Slide your arm underneath your opponents and slide back to finish the armbar.
1) Pummel & Claim Underhook
2) Farside Armbar Finish