Can I select a variant to show instead of the default variant?

The app will display the first variant by default and this behaviour can not be changed.

However, the app shows a built-in variant selector to allow your visitors changing the variant that fit their needs before adding the product to the shopping cart.

Please note that you can change your default variant on your Shopify admin, just go to the the specific product you would like to modify and find the 'Variants' section:

Then you just have to click 'Edit' in the variant you would like to reorder and move it up or down depending on your preference:

Once you are done reordering that specific variant, click 'Done' in order to save the changes.