I see this thread has attracted 4000 views, I’m hoping it’s not all just for the bickering and so I will bore you all a little bit more about planing against a stop.
Start with a bit of board about 3” x 1” x 18“ if when you start planing the edge up against a stop it falls over that is telling you that you are pressing too much on one side or the other and it is unlikely that you will get the square edge that way.
When you first start to plane that edge press down fairly hard with your left hand on the front knob of the Plane this will prevent it bucking as the blade hits the wood, pushing through with pressure from your right hand, when you reach the and if you are still pressing down with your left hand the whole board will lift off the bench against the stop, so this tells you that next time when you almost reach the end reduce the downward pressure from your left hand and press down with your right as well as pushing with that hand, it sounds complicated but it will become second nature after a very short time. And as I said if you can manage to see that video of Mike Siemsen I think it’s called workholding on a viceless bench he demonstrates it perfectly, and it’s well worth a watch for anybody starting out in woodwork, I learnt a few things even after 40 years. Ian