Enjoy your first hammocking trip!  A few hints (from my ~half-dozen overnights):

  1. Sometimes it's easier to get into your sleeping bag before getting in the hammock.  Lay out your groundsheet on the ground next to the lowest point in your hammock.  Step into your sleeping bag's footbox, zip it up, and then sit down in the hammock and swing your legs in.  Zipping up while in the hammock is really difficult.
  2. It's easy to fall off the closed-cell pad.  I've begun experimenting with putting the pad inside my sleeping bag so that I don't slide off it.  Cold Butt Syndrome is definitely a thing.
  3. If it's that rainy, make sure you've got drip lines on your tarp and hammock suspension lines so that they don't funnel water into your shelter.
  4. In case you weren't already, make sure you've got 1"+ tree straps to avoid damaging your trees.
  5. I've hung my backpack by its carry loop from the hammock suspension line where it meets the hammock.  It slightly unbalances the hammock (tips it toward the head or foot - where-ever you hung the pack), but it keeps the pack off the ground and away from your sleeping bag.
  6. Enjoy!