You can set your sub-account quotas during sub-account creation or you can update it by navigating into the account settings.
Click on your current account name in the top left corner of your dashboard (V2) and click on the “Account Settings” button.
You can get to the same page by clicking on the “Settings” button in the main menu on the left.
You will be presented with the form for changing your account details.
Fill in the “Storage quota” and/or “Bandwidth quota” fields with values in gigabytes to set quotas for your sub-account ((Zero) 0 values or no value will grant unlimited storage/bandwidth).
Simply click on the “Save Changes” button to save your new sub-account quotas.