Communicator is not meant necessarily to launch apps that are installed via the Microsoft Store as they may or may not work so well with Windows Control, Gaze Interaction (Eye Tracking), etc.
With that said, you can try this work around. You will place a shortcut to such Apps on the desktop and then launch from the C5 Home Page.
- Exit all programs and close all windows.
- Right click on the Windows Start Menu, select Run.
- In the box, type, "shell:AppsFolder" (without the quotes)
- Select OK.
- Right click on the desired app icon and select Create shortcut.
- Select Yes.
- Close all windows.
- Launch Communicator 5 (C5).
- From the C5 Quick Menu, select Edit Home Page.
- Select Add Page Sets.
- Select Other Files & Applications.
- At left, select Desktop.
- Select the desired app icon.
- Select the checkmark (near bottom right).
- Try out the newly created item on the C5 Home Page.