Newly created tabs are always positioned as the rightmost tab, but it is possible to move the current tab either to the left or the right. The default keybindings have them bound to Alt-< and Alt->. Note, however, that there are problems recognizing those keybindings when using XTerm, so you might want to rebind them.
Several features use bookmarks to save tabs; they will create a folder and bookmark therein the currently displayed document of each tab: