Catholics: WHere in the Cathecism or Bible does it talk about praying to the saints?

I have a project for religion class and I'm supposed to research for my group the topic "prayers asking saints to intercede." I've been looking at the Catechism starting at CCC 2558 (my teacher said prayer starts there) and I'm not done searching but I haven't found anything yet on saints. We can also use the Bible but I'd prefer the Catechism because it's easier to understand. I need to write a paragraph about the background and history of this prayer tradition and then another paragraph for a reflection on how it deepens my relationship with God. So does anyone know at what paragraph this begins in the Catechism or anywhere else I can get some credible information?