You'll need to remove the back panel carefully, which will render the foam adhesive to become useless so will need a replacement foam (available here: http://www.parts4repair.com/back-cover-a...)
Once you've removed the back cover, the camera slides out with no hassle, you'll need to leave the camera module in a bowl of rice overnight, this will absorb all traces of moisture from the camera module. Whilst you're drying the camera module you should also leave your whole phone in the bowl of rice just in case there's some more moisture you're unaware of.
Whilst this is happening, look at your back panel, this will have residue left over from the cover foam adhesive, clean this off.
Once 24 hours have passed, install the new adhesive foam to your back cover, ensuring it is in the exact same position the old one was in.
Place the back cover onto your phone and give it a slight press.
Done.