How to load Dunn and Broadsheet Hierarchy in Customer Data Management

Hello,

We have configured Customer Data Management. We have around 20K customer accounts. We would like to use Hierarchies feature. We would like to load data from spreadsheet with hierarchy type as "Dun and Bradstreet hierarchy". I could not find proper documentation how to upload the file with spreadsheet data.

If anyone has loaded data from spreadsheet, please provide steps how to load the data.

Thanks