Here's the link for an interesting article from a school in Puebla, México. It even has a glossary at the end if you need vocabulary help, and you can click on the arrow to listen as well. Good information and great reading practice! The subject is vast; there is a lot of information out there.
And, if you like movies, try Coco, a Disney Pixar film that takes place at this time. It's available on Netflix as DVD only.
And you can search this blog for an earlier post about Día de los Muertos.