To do so, you will have to use the Cloud Import JSON method for importing assets, as explained below:
Navigate to the Assets tab and click on the Add Data button.
From the dialog that appears, enter the Cloud Storage tab.
Prepare a JSON formatted like the following. It is an array of objects, with each object representing an asset. Each object, will have a data field with its URL, a externalId field with the externalId to be assigned to the asset, and object, classifications, and relations fields according to the type of annotations to be imported.
Annotations must be in the Ango Import Format, outlined in detail in its docs page.
URLs may not contain spaces or "+" characters anywhere.
Drag and drop the JSON you've just created on the Cloud Storage file box:
If your assets are located in a private cloud storage location, select the correct storage integration from the Storage Method dropdown on the left-hand side of the screen.
Your pre-labeled assets with attachments will appear in the Assets tab.