How do i publish a book? please help.?

[art]

I'm thirteen going to turn fourteen. I don't think I'm to young because I'm very mature. I plan on writing a book about a regular teen who falls in love. I'm hoping people can relate to it. My dad says he will help me publish it if my family thinks its a good inof book. I'm still in the process of making it but my question is how do you find a publisher and how much does it cost to publish it and how do you meet the publisher. Or how do you make the cover of your book the way you want it. I just really want to know the whol routine on making a book. Thanks if you could help.