Following are the steps to implement
Migrating data files from SharePoint Server document libraries
Start SPMT, and then enter your Microsoft 365 username and password.
Select Start your first migration.
Select SharePoint Server.
Enter the SharePoint Server site URL where your content is located, and then select Next.
Important
Proxy connections are not supported. Using Proxy connections yields errors such as "SharePoint login fail" or "cannot load document library".
Enter your username and password to the SharePoint Server site; username must use the format of someone@example.com. Select Sign in.
Note
If you have already signed in to that site once while using this tool, you won't be prompted again for the same site.
Select the document library where your files are located. The dropdown contains all your possible choices.
Enter the URL of the SharePoint site where you want your files migrated.
Select the document library to where your files will be copied.
Select Add. This task is added to the list. If you want to select another set of data files to migrate, select Add a source.
Migrating data files from a local file share
Start SPMT, and then enter your Microsoft 365 username and password.
Select Start your first migration.
Select File Share.
Enter the source path of the file share where your content is located, and then select Next.
Enter the URL of the SharePoint site where you want your files migrated, and then select Next.
I hope this information will be helpful!
Mark Wilson