Barcode scanning
If you have barcodes for your products, you can scan them to automatically update your overlays in real-time. Barcode scanning is available on the Overlays plan or higher.

After enabling Barcode Scanning from your Settings, you can go to your Overlays tab to scan your products during your live by placing your mouse cursor in this field:

Each scan automatically updates your overlay.
If you don't already have barcodes, you can use Shopify's “Retail Barcode Label” app to make them. It’s free and just does the basics. You can manually create barcodes in a few clicks to all products that don’t currently have barcodes. And you can print out barcodes as well.

You can use either the SKU or Barcode fields. SoldLive looks at both when you scan a barcode in the Overlays tab.
If you don't have a barcode scanner and need a recommendation, this one is only $35 and works well: https://amzn.to/3mNBMcF