It sounds like you are on the right track by planning a website and considering online sales channels. Amazon can give you exposure, but fees can reduce profits, especially for small production runs. Many small creators start with direct sales through their website or niche communities where people already follow your type of product, like tabletop or wargaming forums.
Marketing will be important, social media, posting photos of your terrain sets, and engaging with the community can help build interest without huge costs. When I was looking into the business side of small projects, I also researched company setup and compliance. Services like
Incorp can help you understand steps like registering a business and handling filings, which makes it easier to focus on creating and selling your product.