Well, first, open the Facebook app or website. Then, on your homepage, you'll find a box where it says 'What's on your mind?'. Click there, type your story, and hit the 'Post' or 'Share' button. You can also add photos or videos if you want to make it more interesting.
It's easy. Just open the Facebook app, click on your profile picture, and then select 'Create Story'. From there, you can choose the content you want to share.