Click the Club Management tab and select "Teams". Click "New Team".
You will give the team a Name, Competitive Level, and Age.
IMPORTANT - When setting the team age, be sure to set age to what the team would be TODAY for the CURRENT SEASONAL YEAR. DO NOT set the age to what the team will be in the upcoming fall. Teams and player are automatically aged up one year for the new season on AUG 1st.