If you buy from some dealer, most will include a "starter kit" It is just a basic's. Then later on get what you want. Whatever you do don't hook up to self contain mode without a water pressure regulator.
I ended up adding extra...25 foot water hose for tank clean out, 25 foot fresh water hose, a fence post to carry extra sewer line and a high quality water regulator. You normally get the quality of what you pay for in sewer lines.
In the mean time...
"Are you gonna pull those pistols or whistle Dixie"?
https://www.youtube.com/watch?v=eQt5WPQTwN0
