After you have downloaded the game and signed up an account, the first step you have to do is create your character. While playing the game, you will be able to have up to eight additional mercenaries in your group, but the character you first create is going to be with you forever and will represent what other gamers see you as.
Atlantica offers you nine different classes to choose from. The names of these classes are based on their skill types. For example, if

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your into being on the front lines and wielding a sword and a shield and being a traditional tank, then a sword class would be best for you. If you are more into the casting and the magic part of the game, then a staff character will be more in line with that. Shuffle through all the different classes and read the short description for a better idea of a specific class.
Unlike other MMORPGs, it generally a good idea to start yourself out with a basic understanding of each class, regardless of which one you choose as your main. As you play the game you will be able to select up to 8 different mercenaries to join you in battle. The mercenaries are simply characters that you control during combat and can add to your group while you progress through the game. The class choices for the mercenaries are the exact same as the class choices you are presented with while creating your own character. So, if you were so inclined to you could actually have all seven classes in your group.
Upon creating your character you can enter a name and a greeting. The greeting is a short message that is displayed to all players in the area when you first log in. After entering that information in click on Gender | Weapon to expand the class selection fold out tab. Click on all of the weapon classes and take a look over their stats and read the short class description. After that, you can modify the appearance of your character by clicking the Apperance roll out tab. When you are done, simply click create and log into the game.