(please read Part 1 first)
Part 2: Domains
A "domain" is an online, text address that people can use to find you on the web, such as "FuzzyChef.com" or "FernhillPottery.net". Getting one is your first step if you are going to pursue any path other than "Social Media + Shared Market" (outlined in part 3). You can also use this domain for your email.
You get a domain by "registering" it with an online business called a "domain registrar," such as Gandi.net, GoDaddy.com, Namecheap.com, or Google Domains. While some online website hosts offer domain registration as part of their service, I recommend against that, since doing so would mean that you could never move to a new host. Annual registration fees range from $15 to $35 a year, depending mostly on the "TLD" you choose, which is that part on the end of your domain: ".com" or ".net" or ".us" or less common ones like ".site". Some specialty TLDs, like ".museum" command premium prices like $200/year, so avoid those (and be careful that your first year is not a discount price).
Now you need to choose a name. Keep in mind that you are trying to register a unique, worldwide name, so your name or the name of your pottery business may not be available; you might have to get creative. The registrar will tell you when the name you want is not available. Use deliberation; you will likely keep this domain for years.
If you already have a registered business name, then try getting that. If you can't, try adding "pottery" or "ceramics" or "clay" to the end of the name. If you don't have a business name, "YourNameCeramics.com" works fine for most people. Also, keep in mind that you don't need to have a .com domain; folks are fine with visiting .net, .us, .ca, .shop, or others these days.
There is an alternative to the complicated path of registering a domain and creating a site, and I'll explain that in Part 3: The Social Media Alternative.