To navigate around Overdrive, use the Menu Bar and drop navigation. The menu bar will display all areas that you have been given access to. Any available sub folders will appear when you click on the arrow next to each menu item, to close the menu click on the arrow again.
If the top menu becomes too crowded and wont fit on to one line, usually when users are opening the site on smaller screens or mobile devices, Overdrive will automatically "collapse" it. You will see a icon appear in the top left. If you want the menu to display across the top consider:
If you want your site to have a consistent appearance you can set the Top Menu bar to always appear Collapsed in Template Designer. To do so:
Overdrive also has a Side Menu panel displaying sub pages that you have access to. You can enable this panel across the site via Template Designer or on each page via Page Settings.
Finally, if the page you are on contains a Folder Tile you will be able to access sub folders, files or blog posts via clickable links.