You can get started here. Don't expect immediate results. Practice the basic "belly" breathing here--slow breaths using your diaphram, especially before using the Examiner or other locator device. Twenty minutes should work. This is the path to meditation. I would avoid the advanced breathing techniques like holding your breath. This can be dangerous and you really need an instructor. Read the warnings.
http://www.abc-of-yoga.com/pranayama/
I really wanted to wait until you have some practice with the rod, but I can tell you to avoid fixating on the rod itself. This is a common mistake when learning any new equipment. You want your awareness on the search area, not the rod. Don't worry, you will notice when it responds.
Also, you want to be several feet away from the target. If you are too close, your energy field will interact with the target's field and you won't feel it. The hottest areas are the edges of the target's field. For a small target this might be a circle six feet in diameter. As you sweep the rod through the search area, try to imagine you have a very long stick and feel for the target's field like it is a big bubble. It's like there is a field membrane where the polarity changes. The target itself will not give as good a response.
I noticed you said you wanted something that works 100%. That's isn't going to happen unless you are perfect. I know ALL skeptics think they are, but that's delusional. The rod is only going to be as good as the operator's skill level. Typically the beginner is going to have mental interference. This might be more than you can overcome, so you are going to have to work hard at eliminating negative thoughts and doubts. If you can get the meditation down, your mind will be still and it won't be "your own worst enemy".
When you are actually searching for a hidden target, you might get more than one response. Put a marker down on each line and try to learn where you went right and where you went wrong.
That's enough for now.