I want to import a list of Customers from CSV file. The problem is, Customer has a lookup field to Salesperson. Therefore, before the import, I manually modified the CSV file to include a column to reference the Zoho ID of the specific Salesperson I want each Customer to be associated with. I map the Sales column property during the import process but the import failed. See screenshot.

So, what's the proper way to import records with lookup fields to other forms?