To set up your Shopify products for Google Shopping Ads, you need to follow these steps:

1. Sign up for a Google Merchant Center account.
2. Verify your website by adding the Google Merchant Center account to your Shopify store.
3. Create a data feed of your Shopify products in the Google Merchant Center.
4. Create a Google Shopping campaign in your Google Ads account and link it to your Google Merchant Center account.
5. Choose the products you want to advertise and set up your targeting, budget, and bidding.
6. Create ad groups and write ad copy for your Google Shopping Ads.
7. Launch your Google Shopping campaign.

It is important to keep your Google Merchant Center data feed up-to-date with accurate product information and pricing to ensure the best performance for your Google Shopping Ads.