On my Android phone, I click in the center of the screen when viewing a book, then click on the three horizontal lines in the upper left corner, then choose "Network library." Mine shows "Search," "FBReader book network," and "Project Gutenberg" as the first three options, and there are many more below those. I've been using FBReader for many years and across at least 4 phones so I may have set it up a long time ago.