I can edit my courses page (I think that's what it is called). It is the page that has my Thinkific URL with the additional longer URL which is edited in the box after the long URL.
I can edit the page which appears at the second, LONG URL.
However, when a user is signed in to that URL and when they click on the shorter Thinkific URL they're taken to what I believe is called my Landing Page -- AND that page is EMPTY and I cannot find out where to edit that page and add content.
Thank you for your help navigating the editing pages soup in the back end of Thinkific. It is so odd that to change one page you must jump between Branding, Courses, Manage, and the Settings gear, and that the Save button is sometimes at the top right of editing pages, other times it is in individual boxes at the lower right of sections, and other times it is at the bottom of the entire page in a footer. It's like using an application that was bolted together by several different developers who didn't have consistent plans. As an end user it is so frustrating to try and update anything on the site using the back end.
Yes the shorter URL is for your site landing page. Once you've published more than one course or bundle, that becomes the homepage for your Thinkific site and your published products will be listed there. If you only have one course published, then the landing page for your site will be the course landing page so you don't need to worry about the site landing page too much.
If you do want to make edits to the site landing page, then in the theme version that you're using, it would need to be done directly in the HTML. That said, we've currently got our brand new Site Builder in beta, which allows you to customize all pages of your site. You can get in touch with our Support team to request early access to that.
The Site Builder also addresses many of the issues with usability that you mentioned, so it's well worth a try :)