There are a couple of simple ways to start brewing. Extract only and Extract/Grain, but before we get into the differences between the two, lets explain what extract is:
Beer is made from fermented grain, but more specifically, the sugars from grain (typically barley). When you add warm water to malted grain, the starch in the grain turns to sugar, and if you separate the liquid from the grain, you are left with very sugary water - add yeast and you get beer. This is obviously an oversimplification, but this is the process for “all grain” brewing which is important to understand when learning what extract is. So, back to the sugary water you made from soaking the grain. If you remove much of the water, you get Liquid Malt Extract (LME), and if you continue to remove the water and totally dehydrate it, you get Dry Malt Extract (DME). These are quality products that are made by the same malting companies that malt the actual grain, they just further refine the sugar to LME and DME.
While extract, both LME and DME, can sometimes get a bad rap from some of the brewing community, the truth of the matter is, if you add water back into the equation, you have the exact same thing during your boil that the All Grain brewers have during theirs. The big difference is of course... options. The malting companies that make the extract use their own blend of grain for what they think will make a good base for your extract beers. These blends usually come in Extra Light, Light, Amber, Dark, and Wheat. Munich and Rye are also available from Briess. Now you can add water to your extract, boil it with some hops and make beer, but these half a dozen options, even if you mix and match them, still will not give you the same control over what is in your beer that All Grain brewers get. This doesn’t mean you have an inferior product per se, but you are limited. Not much more than a decade ago, extract commonly came pre-hopped, which limited your options even further, but today with the increased availability of grain and hops, this method has all but died out.
Enter Extract/Grain. With the availability of fresh grains, called steeping grains, to modify color and taste, along with quality (un-hopped) extract to simplify the process, grain/extract has become the standard for brewers with limited space, someone just getting starting out, or veteran brewers that want a quality home brew without spending the extra time on All Grain. Extract/Grain recipes just require a simple extra step over extract brewing, which is to steep some fresh grain (much like a tea) for 30 minutes before you add your extract. With this extra step you can gain added control of your brewing process and start to dial in exactly the beer you want. Many of the pre-packaged ingredient kits from Salt City Brew Supply are Extract/Grain, and almost all recipe books and magazines will have both All Grain and Extract/Grain recipes.
So, if you want a super easy beer without the added effort of some steeping grains, extract only beer may be a good choice for you, or possibly an extract only beer kit (Coopers, or Mr. Beer). However, if you want more control over the process, color, and flavor of your beer and don't mind a couple extra steps and a little more time put into the beer making process extract/grain may be the right choice for you. There is no wrong answer, and there is certainly no reason not to try different things until you find what is right for you.