How to add Subnet in Existing Vnet using Powershell.

Hi Experts

I simply created one V-net using New-AzureRmVirtualNetwork -Name APAC-Vnet -ResourceGroupName pwsrg1 -Location "east asia" -AddressPrefix 172.0.0.0/16 and I can see a V-net in portal.

But unable to add subnet using Add-AzureRmVirtualNetworkSubnetConfig -name DB -VirtualNetwork APAC-Vnet -AddressPrefix 10.0.2.0/24

Can someone help me to add a subnet using Powershell in existing V-net pls?

Regards Suman B. Singh