Stores cannot modify the /checkout process unless they are on the shopify Plus enterprise plan.
There is no concept of schedulable merchandise sales in shopify , it is not built with any of that in mind.
Any efforts will be multiplied by this fact to use more broad systems to even being to emulate this behavior.
If you are not too far along consider shortlisting other platforms with dedicated features for this type of product and customer frontend experience.
If you must continue you should spend time setting up existing scheduling apps to have some familiarity with the scope of the problem and what the end result will be like for what you build.
Look at just using bookthatapp and it's apis to build what you need initially.
If a merchant cannot access editing checkout then all final information gathering and messaging must be done in the /cart steps of only the online-sales channel; read you cannot affect things like the facebook channels information collection so any "sales" or direct product marketing need to send to a landing page on the online store.
There is no concept of schedulable merchandise in shopify.
There is only things like where the CMS can publish a resource(products/blog-article) at a certain future date. And in the shopify-flow app of delaying actions. None of which has nothing to do with letting a customer dictate the choices of what they are buying.
The most crude concept you can use is variant-options where one of the options is "date" and you fill it with days of the month 1-30, give each day qty's , then just present the 1-30 in a dropdown as is or build a calendar UI to present those variants. Keeping mind a product can only have 100 variants.
Any scheduling,time, data UI's and apis you will have to implement.
Frontend - To attach arbitrary info to a carts line-items use line item properties, or use cart attributes for cart level info.
Backend - To make custom line-items use draft-order/order editing apis. To make products see the products and productvariant api's.
There is also the buybutton or storefront apis where you build the entire frontend stack and really only use shopify for the checkout to get access to all the gateways,etc.
@LuizDMM wrote:
I'm still lost on how to customize checkout or even after purchase experience through a Shopify app. Can someone help me with this?
Just use the dev docs or ask/search much more specific questions.
https://shopify.dev/apps/checkout/post-purchase
You have a long road as your not building an expected typical experience so you've added many many multipliers to the learning curve and should start much more simply and focus on one step at a time problems.
