You can create a team after you've registered for the challenge.
Creating a Team on the Website (App details below - scroll down!)
On the Dashboard, you can enter your details into the "Create Your Own Team" section.
On the My Team page, click on the "Create Team" button.
Then you can enter your team's details. Click "Create" to finish.
On the My Team page, you can invite your team members by clicking on the "Invite Member" button for each open team slot. You'll be asked for their name and email address.
Creating a Team in the App
Open the Home screen, tap on "Create Your Own". On the My Team screen, tap "Create".
On the Create A Team screen, enter your team's details, then tap "Create". You can then invite people to your team on the My Team screen by tapping on "Invite Member" and entering their name and email address.