1. Start PowerShell, switch to your Desktop using cd and use the command Get-AppxPackage to view all installed UWP apps and its data. We'll gonna pipe the output of that command to a .txt file using >, so we can easily search in it later.

    Windows PowerShell
    Copyright (C) Microsoft Corporation. All rights reserved.
    
    Try the new cross-platform PowerShell <https://aka.ms/pscore6>
    
    PS C:\\Users\\tobimori> cd Desktop
    PS C:\\Users\\tobimori\\Desktop> Get-AppxPackage > packages.txt
    PS C:\\Users\\tobimori\\Desktop>
    
  2. Now open the packages.txt we created previously with a text editor of your choice and search for the name of the UWP app you want to start. An entry will look similar this:

    Name              : 28017CharlesMilette.TranslucentTB
    Publisher         : CN=04797BBC-C7BB-462F-9B66-331C81E27C0E
    Architecture      : X86
    ResourceId        : 
    Version           : 8.0.0.0
    PackageFullName   : 28017CharlesMilette.TranslucentTB_8.0.0.0_x86__v826wp6bftszj
    InstallLocation   : C:\\Program Files\\WindowsApps\\28017CharlesMilette.TranslucentTB_8.0.0.0_x86__v826wp6bftszj
    IsFramework       : False
    PackageFamilyName : 28017CharlesMilette.TranslucentTB_v826wp6bftszj
    PublisherId       : v826wp6bftszj
    IsResourcePackage : False
    IsBundle          : False
    IsDevelopmentMode : False
    NonRemovable      : False
    Dependencies      : {Microsoft.VCLibs.140.00.UWPDesktop_14.0.27810.0_x86__8wekyb3d8bbwe}
    IsPartiallyStaged : False
    SignatureKind     : Store
    Status            : Ok
    
  3. To start an app with Stream Deck's built-in System: Open, add that action to your canvas and set the App / File property to the following:

    explorer.exe shell:appsFolder\\<replace-with-PackageFamilyName>!App
    

    Make sure to replace <replace-with-PackageFamilyName> with the PackageFamilyName from the previously generated text file.

  4. To start an app with Advanced Launcher, select the wonderful Windows Explorer from your C:/Windows/ folder (or on whatever drive you installed Windows) and set the Arguments property to the following:

    shell:appsFolder\\<replace-with-PackageFamilyName>!App
    

Make sure to replace <replace-with-PackageFamilyName> with the PackageFamilyName from the previously generated text file.

by @tobimori