I can sure remember the feeling of not knowing where to start with our new RV. I read the stickies here and watched a few YouTube vids too. Stayed in the driveway a few times. Learned to level it and found out how important that is to keep the refrigerator working.
I flushed the coolant and changed the oil--using synthetic as most people recommend it. Had the brakes checked. Bought new tires. Luckily they were replaced in full under warranty and I have new tires again!
I have a complete list of purchases from the first 3 or so years. I must confess I love RV stuff and seem to have a lot. But most of the stuff is very light weight--and foldable to fit in our little RV.
This is the first page of the 9 page list--the rest is on photobucket in the same
folder.
Hope it helps you get started!