Adding players to a team is based on an “invitation” and “acceptance” process. We do this to ensure that players have the choice to accept or decline an invitation to join a particular team. (We don’t think it’s fair for players to be “drafted” onto a team without their agreement.)
So when a manager first adds a player, they won’t yet have access to the team. The manager will notice that a button now appears next to the player’s name: Invite to Join. (Only managers will see this button.) Clicking that button will bring up the invitation screen — it will actually show the invitation status for all pending players on your team. Just indicate which players you want to invite to join (probably everybody on the list) and click “Send Invitations”. (You can also re-send invitations to players that haven’t yet accepted.)
Once you’ve invited your players to join, just sit back and relax. When they accept invitations they’ll create a TeamSnap account and gain access to the site. (And you’ll get an email notifying you of their acceptance.)
In the mean time, you’ll see a label — Invitation Pending — for those players that have not yet responded. Just click the Resend Invitation button to send a reminder.