If you'd like to send gifts by spending the funds in the Team Balance, you have 3 options:
A Team Admin can manually transfer funds from Team Balance to each Team Member's Available Balance.
A Team Admin can give the team member(s) access to spend Team Balance.
Even if you are the Team Admin, you are simply using your Team Member account when sending gifts, like any other Team Member. Meaning you'll need to follow one of the steps above.