Headers h1, h2,h3, and so on...

Well here is some advice that I got from a SEO forum. To help me optimize my site and rank for a particular word. I was told to add headers to the html text. I wasn't told why but I have researched it a little and it looks like google likes it. And that is all that matters to me....One thing I learned before, but obviously forget, was that h1 is referring to a header and the number relates to the size of the text. The smaller the number the bigger the text. It goes from h1 to h6. I also read that search engines like h2 headings along with h1's. If you only have h1 headings it could be considered spam. I guess a couple of years ago spammers would have only h1 headers on the page to rank better. Anyways just something I learned today.