Some students are having a problem with using Blackboard on mobile devices. The theme uses a responsive layout that looks at the size of your screen and shows you a version of the site that fits your screen best. In the case of mobile devices this means that the side menu is collapsed when you first load into a module, so that you have enough room to read the text in the main part of the page.
To see the side menu you need to touch the “tab button” that appears on the left of the screen, see below. This will show you the main menu where you can navigate to the rest of the Blackboard module as normal.