I'm having some trouble understanding how to solution the checkout part of the flow - Do I have to build the checkout system on my site and communicate it over to Shopify Payments (my preferred payment processor), or would it be possible to have them populate a cart on my site, and pass that over with the customer information to a pre-built checkout (like the one you'd use checking out on myshopify.com)?
The only other criteria I have is that they have a full discount on one item, based on their subscription to my website. I believe this can be done fairly easily, and that I have a few options, after looking at the API documentation.
I've read around the documentation but I can't get my head wrapped around the way it should work. Note: This is also the first time I've messed with any e-commerce systems such as shopify!