Welcome new player to RPG gaming. Within the game their are forces (controlled by the GM) that are at constant struggle like in the real world. For these forces a system to detail them is called Alignment. This alignment has two parts: order and intent. Each of these parts of alignment are like two sides of a coin. They must both be present, but never really interact with each other.
Order:
Order describes whether there is uniform structure or just a jumbled mess. Was a house built using blueprints, or was it built by just making a living space by piling the materials up?
Building a house with blueprints, means you are following a set of instructions. Instructions are rules for building that specific house. We all follow rules in our daily lives, so we will use that term for the game that is used in our daily lives: Law.
Law, being a broad term for following a set of guidelines, doesn't means always that it is things that get you arrested if broken. It is simple that uniform structure. Eggs are shaped the way they are because it is the law of the universe, and i'm sure that egg-laying creatures are thankful for it.
Out jumbled mess then is still usable, but follows no form. It could be said to be chaotic in design. Chaos then is the opposite end of our Order part of alignment.
Law <---------------Neutral----------------> Chaos
During their lives people can move between these as some actions may follow law, and others may be in chaos. This means that a shady or grey area appears between when someone is not really one of the other. As seen above, this is the neutral state. As you play the game your actions will either be those that follow some sort of structure (lawful) or just an action without rhyme or reason (chaotic). The GM will weigh your actions and move closer to one side or the other with each action or few actions, depending on how big an impact it made on the game world.
Since, as a player, you choose your actions, you should be aware of what they might mean. Are you doing this as a part of some larger group to work towards some goal, or are you just doing this because you feel like it should be done?
The exact definition of what is Lawful and what is Chaotic should be discussed with your GM and the other players in your game group. A general guideline would be something like this:
Did this action follow some kind of plan and structure within the world, or part of the world i am in, or the being(s) beyond this world? If the answer is YES, then the action is said to be Lawful. If the answer is NO, then the action is said to be Chaotic. The GM will decide how to move you along the line between law and chaos, and let you know if it ever changes, so be aware of your own actions as you play your character.
Intent:
Intent is similar to Order, but describes why the action was done, not how. The house you built from before was built with a blueprint because:
A) someone needs a place to live
B) the house was rigged to kill the person living in it
WHOA! Those two things have nothing to do with why you chose to use a blueprint to build the house. There may have been 1000 blueprints to choose from, but the reason you built the house doesn't even care if you used the blueprint or not.
Intent really has nothing to do with the Order, but must be present. As we can see with our choices above, building a house because someone needs a place to live is something nice. It was a good thing to do. Building a house to kill the person living in it is mean, downright evil. These are the Intent: Good or Evil.
Intent works the same as Order in almost every way, except that it is a separate part of our coin. Though they don't really interact with each other, both must be there to work. Here is what the Intent part of our alignment would look like:
Good <---------------Neutral----------------> Evil
Here there is also a middle ground, and you can move from one side to the other.
What does this mean for playing? Well all actions can be judged by the GM the players, and the creatures in the game world, including being that created the world, and general cosmic powers by checking this alignment. That means you need to choose which you would like to try to be for each half of the coin.
Lawful or Chaotic? Will you play following some set of guidelines when your character takes action, or will your character just do whatever it wants to no matter what other int he world are doing?
Maybe you will be unsure what you want to do and either want to help both, or not really care about either, and choose Neutral instead?
Then you must ask, will you be a nice person or a mean one with your character? Do you choose to be Good or Evil?
Again, maybe your character doesn't know, or doesn't care exactly about either of these which is right? You are just a single character in a whole universe of the game. So you can choose to be Neutral here as well.
We need to pick something for each side of our coin. Is we want to be Lawful we can pick it for that side and write an L on the coin. Then if we want to be Good, we can turn the coin over and put a G on the other side. A character sheet doesn't have sides like this, and flipping the page over to find out would not be fun all the time so after picking for one side of the coin you would right it down. If you are using regular paper and not a character sheet with the Alignment section already there, you need to make sure to write it down so you can tell which place is which side of the coin. Our coin with G and L on it would look something like this:
L / G
Since paper is larger than a coin, we can write the words if we wish:
Lawful / Good
Remember when you do anything in the game this alignment is involved, how important it is for each action will be up to you and your GM to decide together. Alignment is an important part of the game and could cause some drastic changes you can read in other parts of the book, so be sure to discuss it with the other people you are playing with to make sure you all agree on what each side of the coin means for that group of people.