For the full documentation about how to configure the AAD synctool:
Be aware that you need to install Microsoft SQL Server Compact 4.0
To enable Active Directory Sync, login into Workspace 365 environment as an Admin and navigate to Settings page, then to Active Directory section. Check “Enable sync from Active Directory” checkbox and click “Done” button on the action bar. New authentication token will be generated and displayed in the corresponding field.
Click copy button next to the “Sync API authentication token” textbox; the authentication token will be copied to clipboard. You will need to paste this token into the relevant Active Directory Sync tool configuration setting.
By default the "Manage Workspace 365 Admin role from" option is set to "Azure AD". Here you can choose between Azure AD and Workspace 365. When this is set to Azure AD, the users with a IsAdmin flag in Azure, will be set in the Workspace as an Admin.
When this function is set to Workspace 365, you can determine from Workspace which users needs to have the Admin role.
Now the environment is ready for sync requests from AD Sync tool.