I just want to find out how the 'Sell' functionality works? I created a test course and made it so it is sold in the courses catalogue. However, I can order the course and approve it in the backend without ever having to put in any details relating to my bank account information etc.

The E-Commerce's end of FormaLMS is a 90's kind of shopping cart.
Sincerely I used it last time about 10 years ago.
If you need a true e-commerce solution, you'll need a e-shopping integration.

I agree that the built-in shopping cart doesn't offer a very contemporary UX, but it works. Also, in the most recent versions of Forma there have been some improvements.
The reason your customers don't see the bank details is because you didnt' put them in. Go to the language management, look for _WIRE_PAYMENT_DETAILS and edit that key by adding your details.

That being said, if you want an integration with WooCommerce just go to the plugins section https://www.formalms.org/forma-plugins.html