Before you start this tour, be sure that you've read the chapter about Setting Up MH.
Ask someone to send you two or three short mail messages. The messages don't have to be sent with MH. Almost any mail agent will work, although the senders should be able to put a Subject: on the message. You'll use these as test messages later in the tour. They don't have to make sense -- any old garbage will do.
By now, you should have the MH configuration file, .mh_profile, in your home directory -- whether MH created it or the file was already there. If you decided not to follow the suggestion at the end of the Section Setting Up MH about commenting out extra fields, here's another suggestion: As you do the tour, if your commands seem to work differently than the book shows, remember that your MH profile settings may have changed how MH works by default; make a mental note of the words at the start of each field (words like comp: and Editor:).