Myth and folklore: I ordered a pendulum but i need help with how to use it?

I ordered a beautiful amethyst pendulum. I am very excited. It is my first pendulum. I haven't gotten it yet. It should be here in a couple of days. If there is anyone on here that is familiar with pendulum use, any tips or advise would be greatly appreciated. Oh, I also ordered a book to tell me how to use it. I just want advice from someone with experience.