Welcome to the Insiders Community drolma-la!
You've probably been exploring this site and have found it's a great place to discuss all things travel related. It's a great place to read other members experiences & recommendations and sharing your own. It's also a great spot to learn all about the Rewards program. I'm carat and I am one of the moderators here, along with lindseyh and deannad. If you ever have any questions, like above, feel free to reach out to any of us, we are here to help! If you'd like to learn a little more about this site, please check out our Getting Started Guide, linked below.
In regards to your post, I'd like to provide some clarity. A "stay" is defined as consecutive nights spent at the same hotel, regardless of check-in/checkout activity. For example if your reservation contains 3 nights, it is not defined as 3 separate stays, it is only counted as 1 stay. But, you will receive 3 night credits in your account. As a reminder, third party bookings are not eligible for points/nights earnings. Bookings made through Marriott using the AAA rate are eligible. If you have any additional questions, do not hesitate to ask!
Again, welcome! Looking forward to hearing more from you!