The HoloLens app is not yet available in the Windows Store.
Download the ZIP file below and open the project in Unity3D editor version 5.5.2 to compile and install on your HoloLens device.
The PowerPoint add-in is required for the meeting organizer to upload a presentation into the cloud and to share the resulting QR-Code with other HoloLens meeting participants in order to join the meeting.
HoloMeeting-Client Download