How can I add or revise one of the "permanent" tabs on left (Home, Announcements, Syllabus, People Grades, etc.) ? We have an ebook that requires a link to access, and the current Macmillan Learning tab does not connect the students with that (they have to go to Announcements, where I posted the link, or to Syllabus and then the Text section, to access the ebook). I would like to either add a stand-alone EBOOK LINK tab or change the URL for the existing Macmillan Learning tab to actually take students to the ebook access link.