Follow the steps below to add a guest player to your event roster. Player's must go through their individual player account and register for the event as a guest before you will be able to add them.
Once logged into your team account click on the name of the event you are looking to add the guest player for.
Click on the "guests" tab, and then click on the player's name you are looking to add.
Click the dropdown next to "Guests Of" and select your team. Then click update.
Go to your event roster and hit the add guest button at the bottom of the page.