Tip - How do you get a book published? - Ask Dave Taylor

My friend and I are writing a fictional book, it is directed towards teenagers. We are in the very beginning of writing the book. We have just finished laying down the plot and we did tons of research for different characters. We're hoping to get it published but are very confused on actually how to get it published. We were hoping for it to be published by Scholastic but we don't even know how to offer the idea to them. I would very much appreciate if you would tell us how to get a suitable publisher and how to actually confront them with our book.