This is a manual for beginning wizards. If you are a player, you won't get much out of it. You'd do better to read the Map Editor Manual. It's much more useful for Wizard hopefuls than this is. This manual is intended to answer a lot of the questions that new Wizards ask, about .arch files, making maps, and files from the internet. There's also a section about how to behave. Behavior is for the most part instinctive; just be mature, intelligent, and fair. The rest of the Wizardly tasks are less so.
You can learn a lot by doing. Looking through the .arch files is a good way to learn to make your own. If you look closely, what most of the tags do becomes obvious. Learning the finer points of mapmaking is the same way: walk around Legolas' areas or Minath Elion for a while, and if you take them to heart, it's almost impossible to make a bad area. It's just aesthetics.
If you don't know something, and don't "get it" when it is explained on the site (or if it isn't explained on the site!), don't be afraid to ask. If there's a way to do something, somebody knows it. Hopefully, that somebody happens to be a wizard.
One more thing: if there's something not in this manual that you think should be, talk to Ender or someone who can modify the web site about adding it. Don't ask for a complete reference on how to code Java, Python, Jython, and XML. Ask for something "beginner-ish," and we'll see about adding it. Remember, this is a beginner's guide, and it contains what you need to be a Wizard, not what you need to be the most expert computer user on earth.
Behaving like a Wizard
Behaving like a wizard is explained more fully in the Wizardly Behavior guide. This is the condensed version.
As a general rule, you can pretty much decide how to use your Wizard abilities properly pretty easily. It's usually a matter of right and wrong, and we should all know about that. You can pretty much do everything right easily as long as you don't let your emotions get too involved with what you're doing, and treat everyone with respect.
You also have to make sure that you know all of the rules. All of them. Wizards can't claim ignorance of the rules as players sometimes do, because one of the rules for wizards is to know the rules. This includes the Wizard rules, the Player rules, and anything else on the site mentioned in the same paragraph as "rule."
Creating and Modifying Archetypes
Archetype files (or arch or .arch files) are the files for almost every object in the game. Demon Lords have the same basic coding as Kobolds, and Kobolds are only a few tags away from potted plants.
The easiest way to make .arch files is to modify other .arch files. It's fairly easy to do this. All you need is a text editor. Notepad works as a text editor, but it, well, sucks. Wordpad is marginally better. You need an editor that can save documents a plain text in order to work, rich text and .doc formats don't work.
Editing .arch files is explained in the .arch file modification guide.
There are several topics that just don't fit into any other section of the manual, but are important to cover all the same: making teleporters, setpropping, FTP acces, and finally some helpful tips. Real about all of them in the Miscellaneous Stuff manual.