As per my usual routine, if I don't have an explicit idea, I do a search on the interweb for inspiration. Pinterest and Etsy were overflowing with it. Most of the pieces were pretty detailed. This is one of the first things I pinned:
In the interest of keepin' it easy, I chose a theme. I went with a favorite color combination; aqua and gray. So, I chose a bunch of buttons in various tones of those two hues. I really like teal, so the few buttons I had like that were the first I chose.
I'm not doing a big tutorial, here, because I don't recommend this technique. I started in the middle on my chain (by the way, I decided to use a different one than the one pictured) and added my first button. I pushed the eye pin through the back of a hole in the button and used my little pliers to twist the pin around a link in my chain. I used those big-ass pliers to break off the excess.
Next time, I using jump rings. That would be better.
Then, I put a gray button the left, and a gray button to the right, and continued with a pattern. The first button I used was a bigger, shiny aqua one. I decided to layer it by attaching a darker colored one next to it and sewing them together.
I'm not totally in love with my end result, but I'm satisfied because it works and I learned that next time I can use the right supplies. And I'll never run out of the buttons. Here it is: