Its in your manual?
Failing that, a rear light means you pop open the cover in the boot to get access to the lights and change the right bulb.
On the front, offside is accessable straight away, just unclip the two spring clips and remove the plastic cover to get to the bulbs. If its nearside you need to undo the first two screws on the black cover nearest the wing, slide that up and out of the way, that gives access to the same thing - unclip the springs and hey presto.