The extension is installed and connected, but you are staring at a browser full of pages and do not know where to start.
Omni is built around two gestures that cover most daily use: acting on selected text, and asking questions about a capture. Everything else, chat in the side panel, templates, the command palette, builds on those.
Select any text on any page and run a rewrite to see text actions. Then capture the visible area and ask a question about what is in it. For a tour of the surfaces, open the side panel from the toolbar icon and the command palette with its shortcut.