Read your users manual. Play with the MD in you yard or a friends yard, next day or 2 read the manual again. Play with your machine, repeat until you don't learn anything new form the manual. This was advice given to me and at first I didn't think it would be that important since there was not much to the manual.. Guess what it helped A LOT.
Here is a website that will be of great help to you, maybe not yet but as you start to use your machine it will be VERY helpful
These are the articles that helped me the most
Truth About Search Coils Read it a few pages at a time and make sure when done, you come back a few weeks later after you have used your machine a few times and read it again.
Answer to a question you will have within the first week
Halo Effect
link to the list of articles
http://www.metaldetectingworld.com/metal_detecting_articles.shtml
There is a lot to lean, take your time reading the technical stuff, if you don't get it the first time through, hunt a few times and read it again and it will make sense and light bulbs will go on. Many people don't put in the effort to read and understand the technical things that really can make your learning curve much shorter. Understanding how things work in detail really helps you in the field to understand why and what your machine is telling you. You have to take what you read on the forums with some salt.. don't get to into the "finds" other people make as you do not know how many hours they may put into it to find those things. The location you hunt has more to do with what you find than the machine you are using so research of the location is extremely important. Being able to ask permission on private property that may not have been hunted much and has been around for a long time is key to finding old coins. This is an area of the hobby that can be very challenging and difficult (I really hate knocking on doors as I know how I react when a stranger knocks on mine)
Good luck an happy hunting!