You are talking to the program Info, for reading documentation.
Right now you are looking at one Node of Information.
A node contains text describing a specific topic at a specific
level of detail. This node's topic is "how to use Info". The mode
line says that this is node Help in the file info.
The top line of a node is its header. This node's header
(look at it now) says that the Next node after this one is the
node called Help-P. An advanced Info command lets you go to
any node whose name you know. In the stand-alone Info reader program,
the header line shows the names of this node and the info file as
well. In Emacs, the header line is duplicated in a special typeface,
and the duplicate remains at the top of the window all the time even
if you scroll through the node.
Besides a Next, a node can have a Previous or an
Up links, or both. As you can see, this node has all of these
links.
Now it is time to move on to the Next node, named Help-P.
>> Type n to move there. Type just one character; do not type the quotes and do not type a <RET> afterward.
>> in the margin means it is really time to try a command.
>> If you are in Emacs and have a mouse, and if you already practiced
typing n to get to the next node, click now with the middle
mouse button on the Next link to do the same ``the mouse way''.