After you enter their email address on the “Invite Collaborator” button placed on the Sidebar > Account > Collaborators, they will receive an inviting email. Once the invited collaborator presses the “Respond Invitation” button, it will take them to a simple form where they can set up their password.
When they’re done with the form, the next step is them setting up their account.
When done, the collaborator is automatically taken to the main dashboard, ready to proceed.