a)

To get through the door at (5) you need to avoid being seen by the monks at (3) and (4).

b)

Position George behind the large pillar in the centre (1).

c)

Did you notice the pigeons? They helped you out previously...

d)
 

Putting some mouldy bread crumbs on the far right pillar (2) will attract the pigeons, and the monk at (3) goes to the pillar to investigate.

e)


 

This has to be done without being seen by the monk at (4) so study his routine carefully to get the timing right. While holding the mouldy bread, hover the cursor on the pillar (2) and wait for monk (4) to finish tending the plant on the left. When turns around, left click your mouse.

f)


 
Immediately after putting the crumbs on pillar (2) return to behind the centre pillar (1).

Note that George walks around the left side of the pillar to avoid being seen by the monk on the right, so ensure he is facing to the left before your next move.
g)

 
Hover your cursor on the door (5) with the 'door' icon visible and again wait for the monk at (4) to finish tending the plant on the left. When he turns around, left click your mouse, then sit back and watch as George does the rest on his own.