You can follow these steps to create a subscription box using Subify:
Create a product and introduce your membership features on it like this product page.
Open subify and go to the "Subscription rule" page
Create a rule using this new product and add the delivery frequency you want to offer for it then save it.
Follow the steps in this guide, to remove the one-time purchase option.
Customize its appearance on the customization page or contact us to do it for you totally free.