The Iris theme supports advanced product filtering, which requires the official Shopify Search and Discovery App. Once you install the app, take some time to familiarize yourself with it, as it offers several useful features for your store.

To set up the filters:

1. Go to Apps in your Shopify admin and select Search and Discovery.
2. Under the Features section, click Customize Filters.
3. Click Add Filter.
4. In the search field, you’ll see a list of filters currently applicable to your products, which you can add to your filter.

One great feature is the ability to filter products by metafields. This allows you to create more specific search filters tailored to the unique properties of your products.

For example, you could create a metafield named “Flavor” and then set up a filter to search by various flavors, such as almond, chocolate, berry, etc.

To set it up:

1. Go to Settings > Custom data, click Products, and then click Add definition.
2. Name your metafield “Flavor”. In the Select Type field, choose Single Line text, and save it.
3. Next, go to Products in your Shopify admin. For each product you want to include in the filter, add a flavor (e.g., almond, chocolate) in the Flavor metafield at the bottom of the product editor.

Finally, return to the Search and Discovery app and add the “Flavor” filter to complete the setup.