Added kernel install instructions to install-win10m.d

Author: craigloewen-msft

WSL/install-win10.md

@@ -49,6 +49,8 @@ Run the following command in PowerShell to set WSL 2 as the default version when
 wsl --set-default-version 2
 ```
 
+You might see this message after running that command: `WSL 2 requires an update to its kernel component. For information please visit https://aka.ms/wsl2kernel` please follow the link and install the MSI from that page on our documentation to install a Linux kernel on your machine for WSL 2 to use. Once you have the kernel installed, please run the command again and it should complete successfully without showing the message. 
+
 > [!NOTE]
 > The update from WSL 1 to WSL 2 may take several minutes to complete depending on the size of your targeted distribution. If you are running an older (legacy) installation of WSL 1 from Windows 10 Anniversary Update or Creators Update, you may encounter an update error. Follow these instructions to [uninstall and remove any legacy distributions](https://docs.microsoft.com/windows/wsl/install-legacy#uninstallingremoving-the-legacy-distro).