Welcome to the family!
This is an introduction stream, so it’s probably not a good idea to discuss detail here. I’ll start a new posting here.
But in general: For a full-fledged ETL conversion, you will run into a lot of questions like the ones above. It’s probably not a good idea to do this in the Forum piece-meal. What you need is a one-day work session. There are a few folks who will gladly do this for you, but you may have to compensate them a little bit.