Adding/Changing Card info:
First, make sure you're the Admin of the Squad, or the Billing Admin to add a payment method. If you're the Admin or Billing Admin, Click the 3 lines icon next to your Squad's Picture in the top left of the navigation menu.
*For more info on Roles and Permissions, click here.*
Click 'Manage Squad'.
Under your Squad's name select 'Payment'.
Under 'Card Details', click on 'Add Payment Method'.
Finally, enter your card information and email, then click 'Add Card'.