To install Node Version Manager or nvm on Windows do the following.
First, go to https://github.com/coreybutler/nvm-windows/releases and select the nvm-setup.zip file:
You will see:
Unblock and extract the zip file:
As Node.js is already installed, I get this message:
Now, open a command prompt and type:
You should see the version number of nvm, confirming the installation worked: