I know it seems pretty overwhelming right now, but I've been down that road myself, and with other parents and I can tell you it becomes very routine very quickly. I trust that the wee guy will not need the O2 for long, but all of the care etc. is really just common sense stuff. A little more work to feed, a closer watch on his growth and trying not to get tangled in the O2 tubing...: )
El had an NG tube and O2 for the longest time...it's amazing how quickly you go from "OMG be careful!" to "Are you stepping on your brother's O2 tubing again? That's not funny...quit it!"

You'll do great. : )