Very easy, you can just pull the side indicators off with your fingers, twist
the connector so the lens comes off the bulb socket and then just twist on the
new one and click it back in.
The part number is 81731-20220 (double check with Mr T before ordering!) -
this is just for the lens itself (so you will need to order a pair). You won't
need
to buy the rubber seals as you'll be able to use the ones off your old pair.
You'll need a new pair of amber bulbs too (the mini-capless type) but these
are dead easy to get hold of (even Halfords stock these!).
I think it cost me about 20 quid for the pair (from Toyota) plus about 2 quid
for the pair of bulbs (NOT from Toyota!).
Amber
indicator pulled off. Notice the black rubber seal - you will need to pull this
off and fit it to the clear indicator
Clear indicator in place with amber bulb.