As you probably know, Windows PowerShell (the one shipping in Windows) is done, and all efforts go into development of the new cross-platform PowerShell Core. This new PowerShell version is not (yet) shipping out-of-the-box in Windows, so in order to play with it, you need to download it manually.
Fortunately, there is a script that does the heavy-lifting for you. This is how you can download the script source code:
If you’d like to save the script inside a file, try this:
$Path = "$home\desktop\installps.ps1" Invoke-RestMethod https://aka.ms/install-powershell.ps1 | Set-Content -Path $Path -Encoding UTF8 notepad $Path
This downloads the script and opens the script file in Notepad. The script file is located on your desktop, so you can right-click it and execute it with PowerShell to download and install the latest production version of PowerShell Core.