chances are you wont.
first, the hdmi on your tv is likely an input not an output. if its an input it would need to be arc capable if you want to use it at all.
second, hdmi is digital and headphones are analog. you would need to get it converted over to digital. then that signal would need to be amplified so that a device can actually see it (some headphones like the wireless tv ones have this built in so dont need one).
provided your tv has either hdmi output or hdmi input with ARC support you could use a wireless headphone set with rca Red/White input along with a hdmi audio extractor with ARC support that has rca red white stereo output. if you want to use normal headphones instead of something self powered you might need a small amplifier after the extractor