Do what Tom suggests then order the Minelab Exporer and E-Trac book that Andy Sabisch wrote. He's a forum sponsor and probably one of the best in the field when it comes to Explorers. It's 188 pages packed with detailed information about what makes the machine tick and why.
Unless it's a SE Pro or already has another coil on it, use the stock coil for a paper weight and get the SE Pro coil, a SunRay or some of the other after market coils. I couldn't understand what the machine was telling me until I did the coil change. Next, get yourself a pinpointer. The SunRay X-1 hooks right up with the SE and you can hear it in the headphones. It runs just like you disconnected the main coil and plugged in the pin pointer...only you switch from one to the other by throwing a switch. A pinpointer of some kind is a must...specially for a newbie as you can get frustrated really easily trying to find something within all the muck with a large coil. The Garrett is good as is the Pistol Probe. All have advantages and/or drawbacks and some are pricey and others are more reasonable for the working man,, but having one at your side will certainly increase your finds when starting out. Minelabs are not toys. It is a sophisticated machine and takes some time to learn. When you begin, understand their is a learning curve and just stick with it and you will find the things you have dreamed about....Regards...Jim