Step 1: Go to the 'Users' subsection (under 'User management' in the left-hand menu).
Step 2: Click on 'Add User' or 'Add Multiple Users'.
Step 3: Enter the user(s) details and click 'Next'.
Step 4: Select the license you wish to assign to the user(s) and click 'Next'.
Note: If the number of available licenses is insufficient, you can purchase additional ones by clicking on the 'Buy more licenses' link to the right of each license type.
Step 5: Select the role you wish to assign to the user(s), add further details (if required) and click 'Next'.
Note: the different roles are described here.
Step 6: Verify the entered information and click 'Submit'.