You normally click the star icon on the location/address bar to bookmark the current tab. Note that the star has been moved to the page actions area that is part of the location/address bar. If you do not see the star then click the newly added 3-dot page actions button. This menu shows some extra action on you can right-click items in the list to add its button to the address bar. Note that once the page has been bookmarked that "Bookmark this page" will change to "Edit this bookmark", so do not get confused.