Connect the 3.5 mm plug on the audio cable to your computer's Line Out or Headphone jack, and insert the other end into your projector's Audio input.

I have Sony 270ES projector, it is 4k/60hz HDR projector. I have Sony HT-ZF9 soundbar (Dolby Atmos) with rear speakers, so it is 5.1 system. And I want to have HTPC to run it. Problem here is that ...

This post discusses wirelessly projecting and screen mirroring your Windows computer or laptop to an external display like a TV or a Projector using Miracast technology.