Parameter interval in the "paytium_subscription" shortcode is required and can be days, weeks, months. For example if you want charge the customer every 3 days, set it to "3 days".
Parameter times in is not required. Times are the total number of charges for the subscription to complete. Leave empty for an on-going subscription.
The fields with type name and email are also required.
Make sure you enable payment methods that support recurring payments in your Mollie account, at least iDEAL and SEPA Direct Debit, maybe also creditcard.
You can remove this text when you are done. 😉