you can have your bookmarks display on the left of your browser window ,
to do so you need to right click at the top of the firefox window and select customize ,in the new pane that opens drag the bookmarks button to where you want it on the toolbar.
clicking the button will open and close the bookmarks sidebar.
an alternate way to have the bookmark sidebar showing is to click view/sidebar/bookmarks.
i prefer to have the button as you can open and close it with a click.
note: there are two bookmark buttons, one has a dropdown arrow beside it and one is just a star,its the second one you want as the button with the dropdown opens a pop up bookmarks list that dissapears when you click in the browser again.