Redirect Back to Dashboard after form Save?

If you're on the home pages - there is a setting within the button when you create new records that will redirect you back to the home page like so: 

On the Dashboard home pages, its the same concept within each button just slightly different UI

As for the pop up thank you message - you could get creative with a custom page thank you screen with a Javascript redirect, but that route gets difficult given that you don't control all the ways a user could save in Quickbase and control of that redirect. If this is some kind of external user, or a user that will never be editing or viewing the record in Quickbase again - you could also just make a new 'form' in your table that is the thank you message and set that form to display when users 'View' the record, and on that form give them a button back to the homepage. Its not an automatic redirect, but it gets you in the ballpark.