For those like me who closed the page after install and couldn't find anymore how to navigate.
(listing them in the toolbar icon or in the options would help with discoverability a lot)

Shortcut Key

You can use shortcut keys to navigate between landmarks. By default, the keys are:

Next landmark: Alt+Shift+N
Previous landmark: Alt+Shift+P
Main landmark: Alt+Shift+M
Open the landmarks pop-up: Alt+Shift+L, then use Tab and Shift+Tab to move between buttons, Space or Enter to move focus to a landmark and Escape to close the pop-up.

(On a Mac, use the Option key, which is equivalent to Alt.)