This documentation introduces the steps of installing a Windows OS on your VM. Before starting, please be sure that the state bar of your VM is showing green on your panel, which means it is ready for the next step. 

You can refer to

• How To Connect To A VPS Via VNC Over IPv4 On Rapid.Space (Presentation)

or

• How To Connect To A VPS Via VNC Over IPv6 On Rapid.Space (Presentation) (IPv6 required)

to connect to your VM via VNC. 

You are supposed to restart your VM to install a new operating system:

• Click the bottom button to send Ctrl-Alt-Del, the VM should be restart
• When you see the line: Press ESC for boot menu, click Esc as below immediately

Select language and other preferences

Select Custom: Install Windows Only (advanced) since it's a brand-new OS.

Press OK to continue

Now you have the driver list to select. Here we select the first one as default then go Next

If there is no drivers here, please make sure you have virtio-win image prepared as explained How To Deploy A VPS With Other OS On Rapid.Space  

After driver installed, you can select where you want to install Windows on the VM. Here we only have one drive left, so we simply select this one and go Next :

Wait until the last procedure done, press Restart now to get your new Windows.

Set your Administrator's password to login to your Windows.