If you need to add people to your roster, you can go to your team page and navigate to your team's roster tab. From there, click on the blue plus icon next to "Add Players". This will redirect you to the Team Invitations page, where you have the options to directly add players you have played with in the past, or to invite new teammates. Once you enter the new person's name and email address, hit the "Send Invitation" button and the person will receive the invitation email and will be added to your roster once they have completed the process.