I don't have a hybrid but these answers should still apply:
1. We make ice blocks from water filled sealable food containers to help bring it up to temp but still plan on a few to several hours to get the fridge to temp depending on the outside temp.
2. Open the bypass valves, fill heater with water then purge the air from the tank the using the purge valve. Light with gas or electric setting on switch. (more detailed steps in videos on Youtube)
3. Connect to city water and run water until you no longer see the antifreeze. You may fill up the grey tank sooner that you expect so keep an eye on the tank level and dump if needed. I typically get a full hook-up site at the start of the season just to dewinterize.
4. There are good Youtube videos on this...this one is a bit more detailed but gives you the idea
. NEVER leave the black tank valve open. The solid waste needs to be suspended in water for gravity to remove it from the tank when you dump. You will need 3/4 to a full tank to dump and probably the same amount in your grey tank to flush the sewer hose after the black tank is dumped so I would advise not to leave either valve open at a full hook-up site.