Info is organized as a tree (as opposed to the regular man-pages,
in which each entry is organized linearly).
One can go up/down a branch, or go to the next/previous node on the same
level.
To invoke it directly, type in a shell, say, info
lpr (if you want to read the man-page of
lpr) or just info.
To reach Info from Emacs, do C-h i (this takes you
into Info, see the extended choices after C-h).
You can browse the listings on the page you reach (RETURN on any item takes
you into that topic).
Or, you can use m, which offers the menu selections.
E.g., to find information about latex, do m, then
type latex (at this stage you can already use the completion
mechanism of Emacs), and finally RETURN.
? for a list
of commands or h for a tutorial.
A few frequently used commands are given below. In Emacs some of them are enhanced; the extra features are alluded to in brackets.
q- Quit Info altogether.
m- Pick menu item specified by name (or abbreviation).
RET- Follow the hypertext link under cursor (or near point).
SPC- Scroll forward a page (or up/down in the tree).
DEL- Scroll backward a page (or to the previous menu item).
b- Go to the beginning of this node.
l(i.e., lower-case L)- Move to the last node seen in this window.
u- Move `up' from this node.
n- Move to the `next' node of this node.
p- Move to the `previous' node of this node.