....and re-read those. For a first timer, I would really spend some time doing some simple air tests to get accustomed to the different readings you get on different coins and other items. When you first start hunting, set the machine up in the coins mode, notch out the lower cent icon, and just leave open the nickel, high cent, dime, and quarter icons, and notch out the upper two segments as well. That will give you the best chance of finding coins with minimal trash targets mixed it, but you should ALWAYS expect to dig at least SOME trash. That is simply unavoidable, no matter what machine you are using.
You might also just take a few coins out and bury them in your ground to see how they react to your new machine, something you know the identity of before hand.
And don't forget to start out with your sensitivity in the 4-6 range until you get use to the machine a little, and determine how it is going to handle your local ground conditions.
BTW, what part of the country are you in ? Do you know what kind of ground conditions you have there ? Just stick with it, and let us know what kind of problems you are having. There are several seasoned hunters here on the forum that can help walk you through any difficulties or give you suggestions to get you up to speed.
Ralph