To assign roles to multiple users:
  1. Navigate to Core Users/Access > Profile.
  2. Select Manage Roles
  3. Select the appropriate role. 
  4. Select the Members link on the left.
  5. Click the Add button in the top right.
  6. Search for users with the filter options and click Search to display the results.
  7. Click the right pointing arrows (>>) to move the user(s) from Search Results to Added Users.
  8. Click Save & Exit.