To use HDR with the PSVR2, you need to have an HDR-compatible display. If you have an HDR-compatible TV, you can connect your PlayStation 5 to it using an HDMI cable that supports HDR.
Once the PlayStation 5 connects to the HDR-compatible display, connect the PSVR2 to the PlayStation 5 using the included HDMI cable. The PSVR2's processor unit has an HDMI pass-through port, which means you can join the console to the processor unit and the pass-through port to the TV.