Easy to do - after the crank pulley is off (but apparently can be done without removing it.

Check and then double-check the cam timing after fitting a new belt, then triple-check by turning over the engine using a socket on the crank pulley bolt 2 complete revolutions, and adjust as one'll be a tooth out. Easiest to check the cam timing with the rocker cover off.

When tightening the belt tensioner, remember to rotate it clockwise to tighten the belt - the belt can catch on the thermostat housing if you tighten it anti-clockwise.