Not sure if you have the hatchback or sedan but I'm sure they are
pretty similar. If you open the trunk you will see a few screws that
hold the lamp housing into place right next to the rubber
weatherstripping. Once they are out you need to sort of imagine the
other side of the housing (along the side fender) is on a hinge and
swing the assembly around to the side. Once you see it you will
understand but is is very hard to describe.
It moves pretty freely in the right direction so if it is dificult
don't force it. The sockets that give you access to the bulbs are on
the back of the lamp assembly. Just twist em counterclockwise and pull
out the bulb.
Since you have 2 bulbs gone bad I would look at fuses next if these
bulbs don't fix the problem.