The Direct Debit will collect the total balance on your account, including the balance transfer or cash transferred to your bank account.
You could change your Direct Debit to collect either the minimum payment or a fixed amount. Bear in mind this means it could take longer to pay off your balance, and you could pay more interest overall.
You can change your Direct Debit details in the Barclaycard app or Barclays app.
You can also change your Direct Debit details in Barclaycard online servicing.