Congratulations! This is the node Help-FOO. It has an Up
pointer Help-M, the node you just came from via the m
command. This is the usual convention--the nodes you reach from a menu
have Up nodes that lead back to the menu. Menus move Down in the
tree, and Up moves Up. Previous, on the other hand, is
usually used to "stay on the same level but go backwards".
You can go back to the node Help-M by typing the command
u for "Up" (the Emacs command run by u is
Info-up). That puts you at the front of the node--to
get back to where you were reading you have to type some <SPC>s.
(Some Info readers, such as the one built into Emacs, put you at the
same place where you were reading in Help-M.)
Another way to go Up is to click Mouse-2 on the Up
pointer shown in the header line (provided that you have a mouse).
>> Now type u to move back up to Help-M.