PowerShell does not ship with help files, and installing help files locally requires Administrator privileges.
A much easier approach can often be to visit the online help for a cmdlet like this:
Get-Help -Name Get-Acl -Online
This opens a browser and navigates to the online help. Online help often is more up-to-date and easily approachable. It does require internet access, obviously, and there is not always online help available for every cmdlet.
