Please visit Mass File Migrate: User & Configuration Guide
to view the user & configuration guide. This guide will walk you through the required steps to configure and start with the Mass File Migrate.
PS: View Mass File Migrate Salesforce file migration app on Salesforce AppExchange:
https://appexchange.salesforce.com/appxListingDetail?listingId=e9874a66-2001-4e3d-8a29-3a2ed7f584c4