Get-Wmiobject not working

hey guys im sorry for being such a noob on this but im stuck in this very first question,
What is the Build Number of the target workstation?

I’ve tried to run this on cmd after i RDP into the system.\

Get-WmiObject -Class win32_OperatingSystem | select Version,BuildNumber

It keeps on saying the the "Get-WmiObject is not recogniz. what do i have to do?

Has you enter the Power shell? This error message locks like a cmd shell error message. You can try to start the Powershell.exe first.