As someone who has trouble sleeping, I have literally been told by dozens of people that changing a sleep schedule is as simple as setting an alarm to wake up each moring and going to bed at the same time. They have even used this specific saying.
I am not saying that is what I think it means. I am saying that is how a lot of people use and understand it, which is why it is bad advice.
Also, yes I have tried all of those things and they don't work for me. My body wants to wake up midmorning and decades of trying different approaches hasn't worked. I am tired all the time except when I take a vacation and get up when I want, which is about 9 a.m. That is also the only time I ever feel rested.