Not all players come through the online registration form, but you can still enter them manually to your club.
1. Creating new players in your club
Navigate to Admin > Clubs > Select your club > Players > Current (this will be the default landing page for you)
Select the players drop down and click "New Player"
Fill in the details of the player and scroll to the bottom of the page. Here you can click "Create and Finish", or "Create and New" to continue registering further players.