Tip: If you are creating a text box in the Lessons tool, you may also insert activities directly as individual items on the page, rather than within the Rich Text Editor. See How do I add assignments to Lessons? for more information.
The Link icon looks like a chain link.
Alternatively, you can open the Link dialog box with the keyboard command Ctrl + L (in Windows) or Command + L (on a Mac).
The Link dialog box will pop up. Click Browse Server.