UWP: how to install side-loaded app when AppX Installer is not installed on the machine

I need to install a UWP app, side-loaded, onto a machine that does not have access to the Microsoft Store.

This machine doesn't even have the AppX installer app, therefore I cannot install any of those files (that come in the installation package of the sideloaded app):

• msixbundle
• msix

So, two questions:

1. Is there a place where I can download and install this AppX installer app (obviously not from the MS Store)?
2. Can I manually recreate the installation procedure, maybe unzipping the content of the .msix? How can I create the correct folder hierarchy for LocalSTate etc.?

You should be able to install via Powershell on all machines that can run packaged applications:

Add-AppxPackage -Path "C:\Users\user1\Desktop\MyApp.msix"

See more parameters here.

Once you have confirmed that this is working, you have a number of different choices on how to run that command in a way that average users understand.

For example, you could create an Inno Setup Installer that runs that command like this:

; Just the relevant snippet:
[Run]
Filename: "powershell.exe"; Parameters: \
  "-ExecutionPolicy Bypass -Command Add-AppxPackage '{tmp}\MyApp.msixbundle'"; \
  StatusMsg: "Installing application...."; \
  WorkingDir: {app}; Flags: runhidden

Edit: Maybe you could also try to restore the built-in applications users might have deleted? In Windows 10 you can do that by running:

Get-AppxPackage -AllUsers | Foreach {Add-AppxPackage -DisableDevelopmentMode -Register "$($_.InstallLocation)\AppXManifest.xml"}