Office 365 Activation Confuson

I just installed Office 2016...I got these directions to follow but they're a little vague:

• Activate - me: done
• Sign in with an active account instead - me: what?
  • Use account you were supplied supplied
  • Uncheck stay logged in
• Accept defaults
• Use Recommended Settings
• Do not login

Are there two separate accounts at play here? Why shouldn't I login with the last one?