Hi there @TheResinator .
I’ve taken a look and it appears that the theme Craft does not have the “variant picker” block included in the product page template by default. This means that without adding the variant picker manually, your customers won’t see variant options on the storefront.
You can add the variant picker block by going to Online store > Themes in your Shopify Admin and clicking Customize next to the theme you are working with. Once in your theme editor make sure you are editing your Default product page and then you can add the Variant picker block into the Product information section.
You can see an example of what this setting looks here:
This will allow your variants to be displayed and selected on your storefront as long as you are adding variants to your products correctly.
For reference, you can find the steps to add variants to your products on this page here. You can also read more about using sections and blocks within your theme editor on this page here.
Please let me know if you try that out and are still having trouble with it. I’d be happy to troubleshoot this further if you need it.