This is result of your instructions (I triple checked this):
Add-AppxPackage : Cannot find path 'C:\AppXManifest.xml' because it does not exist.
At line:1 char:53
- ... | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.I ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : ObjectNotFound: (C:\AppXManifest.xml:String) [Add-AppxPackage], ItemNotFoundException
+ FullyQualifiedErrorId : PathNotFound,Microsoft.Windows.Appx.PackageManager.Commands.AddAppxPackageCommand
Add-AppxPackage : Cannot find path 'C:\AppXManifest.xml' because it does not exist.
At line:1 char:53
- ... | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.I ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : ObjectNotFound: (C:\AppXManifest.xml:String) [Add-AppxPackage], ItemNotFoundException
+ FullyQualifiedErrorId : PathNotFound,Microsoft.Windows.Appx.PackageManager.Commands.AddAppxPackageCommand