Adding bookmarks with shortcut keys

Hello, everyone, first time here. I have a question about shortcut keys for adding bookmarks. The shortcut is Command + D to bring up the bookmark dialog box. But how do I tab, or move down to, the 'Create in' field or the arrow button to the right of it? I guess the question is, how do I navigate the dialog box without having to resort to the mouse all the time, which is irritating. Any help would be appreciated.

Thanks, Bix