Welcome to the forum:
Sit down with the owners manual and study it like you are studying for the bar. There will be a test for sure. Multiple tests and at times not very convenient.
These are complicated Phone Booths with lots of strange systems. It can take months to get comfortable with them and even then you will forget things if you are a weekender. Heck, we live in ours and I still forget things. Could be other issues with that for sure.
When you are reading keep a highlighter and notebook handy. Its your book (books), so go ahead and make notes in the margins or where ever. I often put page numbers on the covers to remind me of quick places to go.
This is a fantastic forum and help is usually available within minutes.
As for that noise that the Tardus makes, if your RV ever makes that noise please do not contact me.