Go to Configuration > Products > Products. Make sure the product is “Bookable via Internet”.
Go to Configuration > Web and app > Web categories. Make sure the product is added to a web category.
Check “Display period” on the web category to make sure the dates have not passed. If it’s empty the web category will be shown immediately and until it’s removed.
Make sure “Show on customer web” and “Show in app” is checked in.
Make sure the web category is added in Web and app > Apps.
Why is the instructor's name not shown on the class on the web/app?
Make sure the resource for the instructor is tied to a staff:
Go to Configuration > Staff and resources > Resources
Find the resource, make sure the "is staff" box is marked and that it is connected to a staff: