I completely understand! Not too long ago I was in the same position. I’ve actually gone through a fair few before two that fit for me. I have one that’s an amethyst and one that’s a quartz with a wee wolf charm on it. As for using them, well, it’s quite simple, in truth. Hold the pendulum in your dominant hand, as steady as you can (I sometimes rest my arm on a table or on my knee), and ask it to show you yes, say thank you once it has, then ask it to show you no. Thank it again once it has. (All of the “spoken” bits can be done in your head if you’re more comfortable doing it that way. I know I am!) Then, simply ask it your question. The more you practice the easier it will become, of course.
For practice, you can try testing yourself by having a friend or family member hide something (a book, a lipstick, what have you) and use your pendulum to find it by asking yes/no questions.
It’s okay to need some encouragement, especially when you’re just starting out. But don’t worry. The more practice, the better. You’ll be amazed how quickly you’ll grow in your strength using it! If you have any other questions feel free to come back!