Direct swap....
Take of the 3 bolt covers on the old lightunit, then remove bolts.
Be a little careful with taking out the old one. You can see on the new unit how the plastic pins are lined up.
Take off electrical connector.
Clean the area now as you have easy access to it
Connect the elctrical connector the new light unit.
Install new light unit.
Re-use old bolts and covers.
Done!
P.s., while you're taking off the light units anyway, replace the orange indicator bulbs with silver ones! You can access these via the gap after removing the light unit.
find them here
They do a set for the 350z, for front/rear indicators. If you want the side indicators as well, look at a pair of the 194/168 sizes.