cut the flower out with 45 degree angles, shallow slice the skin top to bottom at quarter intervals, you can crack it open, takes practice.

Alternatively, you can open them underwater in a large pot, picking out the pith, if you do puncture a seed or 7 it won't make a huge mess.

I had actual pomegranate juice from the side of the road, from a literal four sticks and a tarp set up with a hand cranked, 100 year old looking juicing contraption. The man selling was weatherbeaten and old as fuck, but when I had my drink and the I have seen the light look on my face from tasting proper, real pomegranate juice for the first time, he chuckled and told me he sees that face very often.

It’s a whole rabbit hole of tutorial videos. Try all the different methods to see what you like. I think the “restaurant style” might be your thing though. It involves doing the whole thing in a bowl of water.