How do I test a new add to cart function in Shopify when using Maker Nav?

How do I test a new add to cart function in Shopify

Here are the steps to test a new add to cart function in Shopify before going live on production, if using Maker Nav

1. Create a duplicate of an actual Nav in your account

2. In that duplicate, change add to cart to a custom function that points to the Add to cart (new)

3. Embed it somewhere in a test file in Shopify (for example: https://brand.com/pages/test-add-to-cart)

4. Test it on Shopify's preview link. Shopify gives you a preview link for any theme even if it is not live or published