This extension uses the Azure RM PowerShell New-AzureRmDeployment cmdlet for installing ARM template in Azure DevOps. The cmdlet does not support a ResourceGroup name parameter so you find that input filed missing in the extension.
This also means that all information required to configure the resource must be present in the template files.
The extension can handle nested templates, so you can make your configuration as compleet (or complex) as you like
Help & Contact
The source for this extension can be found at https://github.com/hansvanveen/AzureRMDeployment Support requests can be send to firstname.lastname@example.org