How can I get the old tabs at the top of the page back, like before, in words I can understand.

This is filed as Firefox for iOS (=mobile) issue, however its tab positioning settings are pretty much pre–set — are you perhaps trying to solve an issue in macOS/desktop browser and not mobile? When you say "back on top", "like before" — has something changed in your layout? And the tabs are not shown at all, pages are not opening in separate tabs, or you perhaps moved from horizontal tabs to vertical tabs by leveraging the sidebar? See [[Use the sidebar to access tools and vertical tabs]] where the first image shows how to switch from vertical to horizontal layout, if that's what you're struggling to find.