Login to your app as a member

Go to the Studio tab of the app >> click on Subscription and select the subscription of your choosing

Then, you will be able to see all the subscriptions available and to select the subscription you want

Once you selected it, you will have to click on Payment

Finally, you will be able to Vous pourrez alors Add a payment method and validate your purchase first by selecting the payment method you just saved then by clicking on "Bill"