Welcome aboard! We're glad you wish to help develop Wikipedia, and hope you enjoy participating in its community as much as we do. As a new contributor however, you may feel a little overwhelmed by the sheer size and scope of this project... but don't worry, it will become easier and clearer as you go, and if you have any problems, there will always be other Wikipedians happy to help. There are some resources set forth below to help you get started. Good luck and have fun! -- The Wikipedia Welcoming Committee
To understand Wikipedia, it is easiest to think of this website as having two types of pages: pages that are part of the encyclopedia itself, and pages of the community (used by contributors to help build and operate the encyclopedia).
There is a quick and easy way to find community and project pages: Almost all "Wikipedia-space" pages have shortcuts that take you directly to the page you want from whichever page you are currently on. Most of these shortcut redirects are just abbreviated forms of the page's title. To use a shortcut, in the search box simply type WP: followed by the word of what you wish to learn about. For example, if you wish to learn what primary sources are, you would type WP:PRIMARY in the search box and hit enter, or if you want to know what NPOV means, just type WP:NPOV (it doesn't necessarily need to be in capital letters) and it will take you straight to the relevant page. This is also why you sometimes see short notes at the tops of pages saying things like "WP:FOO" redirects here. For <blank>, see <blank>., it's to ensure users arrive at the correct destination. Experienced and established users navigate throughout Wikipedia using this method and it's also a great way for new users to find their way around.
Some directories to help you find your way around the community are:
If you've made a mistake and wish to undo it, revert it. Here's how: click history at the top of the page you made the mistake on. Then click on undo at the end of the first line which is your edit. Then save page. See more detailed instructions at Help:Reverting.
There are two main styles of help on Wikipedia: self-help and assistance...
Self-help involves reading the help and instruction pages around Wikipedia. Some very informative self-help pages are: