On your browser, go to facebook.com/products.
Choose the store you created on your Facebook page. (tap here if you haven't done this)
On the left menu, tap on Product Data Sources.
Click on Add Products
Tap on Use Data Feeds.
1. Select your currency, 2. choose Set Automaticr File Upload Schedule, and 3. Include your catalog's URL adding /feed at the end.
Now you have to wait some minutes for your products to get uploaded on your Facebook Shop.