in the start of the config.js you will find this code
shopifySite:"https://mobidonia.myshopify.com", //Link to your shopify store
firestoreCollectionForCategories:"product_collection_shopify", //Where to save the collections
firestoreCollectionForProduct:"products_shopify", //Where to save the products
cronInterval:"00 59 20 * * 1-5", //How ofter should the cron job run https://github.com/kelektiv/node-cron
The above code sets up the script. What you have to do is just replace shopifySite with the link to your Shopify site.
The cronInterval set how often the script should be called.
In the example above is Monday - Saturday at 20:59
Read more here https://github.com/kelektiv/node-cron