First action: Create a Storage Sync Service
The deployment of Azure File Sync starts with placing a Storage Sync Service resource into a resource group of your selected subscription.
Second action: Install the Azure File Sync agent
The Azure File Sync agent is a downloadable package that enables Windows Server to be synced with an Azure file share.
Reference:
https://docs.microsoft.com/en-us/azure/storage/files/storage-sync-files-deployment-guide