That depends on where you want the barcode to appear. For example, if you want it to be shown on a single product page, you need to enable the “Barcodes” or “2D Barcodes” section (in “WooCommerce > Settings > EAN”), and there enable the “Single product page” checkbox.
Hope this helps. Please let me know if you have any questions.
P.S. Also, if you wish, you can share access to your site, so I could log in and help you with setting it up (my email is [email protected]).