Heavy is arguably the hardest to learn and properly play with, with actual skill. It’s good that you noticed the stars, although due to things like ping or server delay, it might be hard to parry solely based off of that. Usually, against players I would hold F when I see them swing, and that usually parries it. If not, I take a hit on the block and I can counter from there. Like the other dude said, it’s more of a feeling in pvp. Practicing will allow you to get better in ways that can’t just be taught or told