Thank you for your post!
I do understand your concern with this. When setting up a Direct Debit, there are 4 different options available. If you choose to pay the minimum amount, your monthly minimum repayment will be shown in each statement and in the PayPal Credit section of your PayPal account.
Your minimum repayment amount is calculated based on your purchases. When your Direct Debit it charged from your chosen bank account, it will go towards paying off your owed balance.
For further details, please click here.
I hope this helps!