Take the biggest button. This one will be the base button. Now take a small button and spread glue on the back of the button. Carefully paste it on the top of big button.
Take six small buttons and fix them under the biggest button. Arrange them like the petals of a flower. Glue the buttons to each other and let it dry.
After the glue has dried you can glue on the ring base. You can use either a ring base or a plain ring, according to the availability. After putting glue on the ring base, paste it carefully to the back of the button. Use enough glue, but not so much that it oozes all over.
Here we have done with the ring. Now it is ready to wear. Try it with different colors and patterns and arrange the buttons according to your wish.