Hi Maddy, Here's one way you could go about doing it. You'll need to learn some animation software. Here's a nice list for some applications you can download - http://www.toptenreviews.com/software/multimedia/best-2d-animation-software/
Pick one of these to learn and download it. Many companies offer their software for free to students, so it might be worth checking out. Once you've picked a program to learn, start watching tutorials on youtube, for example, to learn how to use the software.
It won't be easy, but that's just the way it is at first. And it will ALWAYS take a lot of work. Don't let that discourage you, but just be prepared to work. The more you practice and improve your art skills, and learn the software, the easier it will be.
This should get you of to a great start.
Good luck and happy animating!