First, make sure you have successfully set up your GoCardless Mandates.
Navigate to Sales > Invoices > Recurring.
Click on the Create Recurring Invoice Template button.
Fill in all the required details of the recurring template.
At the bottom of the page select, GoCardless as the bank account in the Bank details to display drop-down box and tick the Attempt to collect money automatically from customer checkbox.
It is important to use the Bank details to display drop down box and not the Create payment on recurrence option.