To begin, navigate to the cog at the top right>students section, and click on the names of the students you would like to invite, or select all students by clicking the 0 box at the top left of the page. Then select the envelope icon at the top of the list.
You will be prompted with a 'Invite Students' pop-up to confirm the students you wish to invite, once confirmed click 'Invite Students'.
Note: The system will detect if there are pending invites, and send reminders and skip over any student who is already connected. If you have setup Single Sign On, change the dropdown shown in the below photo to the authentication profile you have created and then select invite.