To add additional users or locations to your account, click on the "Users" tab:

Then click on the "+ New User" button:

Fill out the form that has opened up (seen below). Make sure the Time zone is set properly to ensure Schedules and Messages play back at the right time. 

Note that if you would like to remove some or all of the music options from a user (or users) you can easily do so through the "Assign" button. More info is here in our Assigning music to Sub-accounts guide.