Menus contain pointers to subordinate nodes. In online output, you use menus to go to such nodes. Menus have no effect in printed manuals and do not appear in them.
A node with a menu should not contain much text. If you find yourself writing a lot of text before a menu, we generally recommend moving most of the text into a new subnode—all but a paragraph or two. Otherwise, a reader with a terminal that displays only a few lines may miss the menu and its associated text. As a practical matter, it is best to locate a menu within 20 or so lines of the beginning of the node.