You can work upon one of the many tools that exist for this exact purpose:

1. You can use aMember to create a standalone membership website.
2. You can setup a Wordpress website and install a plugin like "MemberPress", "Paid Memberships Pro" or a combination of plugins like "Woocommerce + Groups + Subscriptions".

It all depends of what sort of interaction you want for your customers. Take a look at those options and see if any of them match what you are looking for.

Of course you can create something from scratch but that takes time and usually a lot more money. Make sure what you need doesn't already exist before venturing into a fully custom job.

Best of luck! Let me know if you have any more questions!