Its the same as the 757. There are trigger switches on the back of each throttle.
Trigger either one of these and the thrust will go forward to max go around thrust. The autopilot / flight director will go into go around mode (approx 15 deg up). The thrust will the come back to reduce the rate of climb to 2000 fpm automatically.
The PF will also call Go Around Flap 20, and the PNF moves the flaps from 30 to 20 as you pitch up.
Quite straightforward really.