1. Add a product card block from the "Store" category.
2. Open the Content panel of the block → Variants → Add option.
3. Enter the "Option name" in the field on the left. Then enter the option values with a line break between each value in the box on the right.
4. If the option value differs from the base option, add "=" and its price (numerical values only).
5. Save changes.
6. Add a shopping cart to the page. Publish the page.