Query on Azure Files

Hi Experts,

Need your input here. We have a Azure Windows File server (with data around 40 GB) which now needs to be migrated to Azure Files and those SMB shares are being accessed by multiple applications & end users using DFS-N. Could you please suggest firstly the migration tool which can be used for this effort? I am sure, there won't be need to use Databox for this effort, as data is already in Azure on a windows file server (VM) & now it needs to be moved to Azure Files. Secondly a detailed migration approach would be great to have. 

Can anyone please share high level steps?