I am 15 years old writer. how can I publish my books?

That's easy, if you have patience. I'm 14, I'm a writer, I've been writing for two years and have had three books published and out of those books I've earned $136. Which is a lot for an author just starting out. It's easy, I have an iPad ( if you don't have one it's okay. ) and I have this app, " My Books" which lets me upload my books to iBooks and iTunes. You have to pay $4 for it, if your interested of course! But there's other ways,I'm a freelance writer, I enter contests, ( you can enter some now at freelance writing.com) which pay $10 bucks to $20,000 bucks, but the larger the cash, the more people who enter. This is a great place to find a book company and get your book published because usually it'll give you a cash prize, have you read your story, then publish your book on natural television. Then, if a company likes you, your hired! I haven't gotten hired by a company YET, but I'm on the way.
I hope this helped! If it did please put it as helpful so I can give more advice to people so they can know I'm a good person to talk to! Best of luck!