Good to see someone close by.
I'm confused, the post title says camshaft sensor but the text says crankshaft sensor. Do you mean the crankshaft sensor (PN 5066882AA) located on the lower rear passenger side of the engine and hidden behind a heatshield. If so it's held on by one bolt once you get the heat shield off and replacing the "O" ring should be no problem. Or do you mean what the parts manual calls the camshaft sensor (PN 5140332AA) which is actually the MAP (manifold absolute pressure) sensor located on the top of the engine back toward the firewall; see the first image on Sam's NOOB guide at
viewtopic.php?f=5&t=54207 . If so it's held in place by an allen head bolt and has a tiny lock washer which is easily dropped but not critical as long as you don't drop it into the engine. Removal can be done without loosening the top of the engine wiring harness but doing so helps. If you do remove the MAP sensor it will need cleaning per the NOOB guide and be careful not to get the black goop on anything you don't want perminently stained black.
Either way I have a nice little rounded dental pick that is wonderful for lifting off an old "O" ring; lightly oil the new "O" ring and it should just pop right on; apply a drop more oil to the "O" ring once it's on the sensor and insert the sensor into its seat with a slight twisting motion to slid it into place; reinstall hold down bolt.