If you look at the menu bar at the top of the forum web page, you'll see an item titled "Library." There's a lot of stuff in there on your questions. Without knowing make/model of your furnace/fridge, we can't help you much. Try to get those and re-post. You can also google them online and see if you can get an owner manual online.
With respect to the fresh water tank, you'll want to fill it with clean water with 1/4 cup bleach to 15 gals of water added. (You may have to add water 1 gal at a time if you don't know how big your tank is.) Pump some through the lines to your faucet/toilet. Let it sit a few hours, then drain it, then refill/drain a few more times. You do this every Spring. I can't tell you anything on your toilet, I suspect it's one of those "cassette" things - don't know much about them.
If you don't have a grey water tank, you'll probably need to buy a portable tank so you can collect your grey water and take it to the dump site, or dump down a toilet at the bath house. (Illegal to dump it on the ground.) I used one like this for 20 years with my Popup:
Barker Tanks 5GALTT
It was easy to carry and I kept it clean on the outside, so it traveled under the dinette table. There are bigger ones with wheels, if you think you'll be generating more water. I usually only had to dump mine every couple days with a wife and 2 kids.