To manufacture items and ships, either for yourself or to sell for profit, there's a few simple things you'll need. First, you'll need to purchase a blueprint, either a copy or an original. The easiest way to find one is to open up your Market and go to the Search tab. Let's say you want to make, and sell, a Rifter--a Minmatar frigate. Enter Rifter into the search; you'll get two results: Rifter and Rifter Blueprint. Clicking on the Blueprint will show you how much they are and where they are for sale. Clicking on the blue "i" will give you Information about this blueprint. You'll see a Manufacturing Time and a Manufacturing Time (You). The Manufacturing Time is the base time it would take to build one; the (You) is how long it takes you, with whatever skills you have to speed things up. Ignore the Researching for now; Researching a Blueprint will make it take less time and less materials to build, or create a Copy, depending on which Research you're doing (for now ignore this; we will talk more about Copies later).
Below, you'll see this:

PRODUCES
Rifter [1]

This means that when you put this blueprint into manufacturing, it will create one Rifter. The information below, regarding material level, wastage factor and productivity level, is the base quality of the blueprint; you can Research it to make it more efficient.

Basically, what all this means is that it would take 1 hour and 40 minutes (or whatever it says after "Manufacturing Time (You)") to create One Rifter.

Now let's have a look at what else you'll need. Click on Bill of Materials. Now, you'll notice that you need no special Skills to produce this ship. You'll also see that you need Isogen, Megacyte, Mexallon, Nocxium, Pyerite, Tritanium, and Zydrine, and the amounts of each you will need (after You:). These are minerals, which you can either buy off the market or get by refining the correct ores (see the Mining Guide for more). However, this isn't quite it. Go back to the Attributes tab of this blueprint and have a look far down on the bottom; it says Wastage Factor. Wastage Factor: 0.1 means you'll need 10% more of each mineral. So when it says that you need, say, 500 Isogen, you'll want 550 instead.

Once you have this all together, and once you've bought the Blueprint (these can be quite pricey, so be prepared to pay a large sum--and make sure that the route to this blueprint does not cross low-security space, as you might then lose the blueprint to a pirate on the way back), you can begin. Right-click the blueprint from your Items, and pick Manufacturing. Select your station from the first drop-down menu (or if your station is not on the list, go to the nearest one, and bring the blueprint and minerals) and then select your blueprint. Pick the number of Runs you want (if you had enough minerals to make two Rifters, and you wanted to make them, you'd pick Two, as they are one unit per blueprint run), then choose an assembly line that fits your needs--one that doesn't cost too much and has free time when you need it. Now make note of when it will be done. Click Use Assembly Line. The station will then formulate a price and mineral quote; click OK. If you are missing anything needed to create the Rifter (for example if the Isogen was accidentally left at another station) the production will now cancel and inform you of what you're missing to complete the job.

Otherwise, your Rifter is now in production. After the correct amount of time has passed, click on the far-left tab Science and Industry (beneath Market and Mail). Go to the far right of the window that pops up and select Get Jobs. You'll see yours, and under State it should say (in green) Completed. On the bottom right, click Deliver (if it says something in yellow, it isn't done yet--remember, two runs take double the time). Then you can pick up the blueprint and the Rifters at that dock.

Selling Items: Don't just right-click on an item and select Sell. Sell will sell to whoever has what is called a Buy Order out. Anyone in Eve can place a Buy Order (to offer money for items) or a Sell Order (to offer items for money) at a specific dock, and you may accidentally sell it for far under what you could be getting. Instead, right-click it and View Market Details. You may choose to bring the Rifters elsewhere and sell them, or you can right-click and pick Sell Item, then pick Advanced. Here you can select your Asking Price (the Eve Regional average is not always accurate, so ask around if necessary), the Quantity (the number, for example if you had five hundred Nuclear S but wanted to sell only 100), and the Duration (best set to at least a week). It will show you how much it will cost you in sales tax and as a broker's fee, and then you can click Sell if it's all okay with you. In this way you may not sell things immediately but if they do sell, which they usually will if they're not for sale in the area otherwise, they will sell for a better price than you'd get by clicking Sell. Incidentally, you can work the other way around--if there's something you want to buy and it's expensive, you can create a Buy Order to see if someone will sell it cheaper.

Blueprint Copies versus Blueprint Originals
So far the Blueprint we've been referring to was an Original, purchased directly from the Market. An Original has an unlimited number of runs, or manufacturable units that can be created using it. In addition, from an Original, one can research a Copy. Copies look just like Blueprints, except that on the Copy, you'll see a "Licensed Runs Remaining:" down on the bottom of the Attributes tab of the Information. Copies are usually purchased from Escrow rather than the market. If a Blueprint Original is well-researched, meaning more efficient production, the Copy will be more efficient as well. This, combined with the much lower cost of buying a Blueprint Copy, means that often a Copy is a more feasible purchase than an Original, especially if the buyer just wants one or two runs of the item in question.

How To Use Contracts, and How To Tell a Copy from an Original
First, dock your ship in any station. On the left, there's a button called Contracts; click this. To search for items--and this is pretty self-explanatory--leave the Start page and move to Search. Change the search fields depending on how far you're willing to travel, on what object category and type you're looking for, etcetera.
When you find what you're looking for, right-click and select Show Contract. Take a look at the item and make SURE it matches what the contract name--if the seller says it's a Blueprint Original, you can inspect and it will say, under the category Original? either Yes or No. In addition, if the seller says it's a copy with six runs left, you can look under info at Licensed Runs Remaining and see if he's telling the truth. If all is in order, double-check the Location and Price; you don't want to pay too much, nor do you want to travel through or to low-security space as a new, inexperienced player for something expensive! If this, too, is all suitable, then buy the blueprint. You'll then have to travel to that dock and pick up your item (you can Search for the item in your Assets, the golden safe above your wallet on the far left, if you forget where you bought it, or you can check your past contracts to see where it had been).

If you like, you can make Copies of an Original Blueprint and sell them on contract. Or, you can buy the Copy from a contract and manufacture the item. It's all up to you!