Before starting auto-tagging your photos, you need to get Google Cloud Vision API key and activate it in Daminion server administration panel. Please learn how to do this here and here.
Once Auto-Tagging is enabled in Daminion server administration panel, open your shared catalog in Daminion desktop application.
Select one or more files, right-click them and navigate to “Actions > Generate AI Labels”. Alternatively, click the “Item” tab and navigate to “Actions > Generate AI Labels”.
The process can take some time. You can monitor the number of generated labels via Tags Panel > AI Labels.