Stocks fall because those who choose to sell at that price are more motivated or have more money than those who choose to buy at that price. We can't know more than that - anything else is just stories we tell ourselves to foster understanding.
Any number of things — mainly random aggregations of orders. Institutions by and large trade dark or through algos that track a % of adv. Anyone telling you that a spike in volume is institutional buying is lying to you. I’m not saying that there aren’t ways to track institutional buying, but those are beyond a simple price and volume chart. And you’d still lose money at 50% because you have to pay the bid/ask spread. Simple maths. Anyone who claims they can make money on a 40% edge merely does not understand their claim lol.
In Forex there is big hype with courses that say "Smart Money Concept" its same as supply and demand just a fancy name for it, where ppl make like 700RR a week its nothing but the mentors making money form the course and 80% aren't even real traders just slapping the risk reward tool on the charts and showing 100% gain in a day and trapping the beginner traders . its a shame the Big whales/hedge funds of course manipulates the market that's what pure supply and demand is
I question whether a 40% win rate and a 40% edge are the same thing. I tend to make more money with my winning trades than I lose when I get stopped out. I'm not sure if you can define that as an edge.
I always think of it in terms of pressure. On the sell side you have those closing their long positions for whatever reason. You don't know at what price the got in, it could be profit taking or covering losses, and then you have new shorts entering the market.