Help:How to edit a page
The most essential element of all wiki projects is the ability to edit a page. All pages (except protected pages) give participants the ability to modify them. This can be used for anything from a simple spelling change to a complete re-write.
How to 
First, you need to read the whole page, make sure what you are saying hasn’t already been stated. Then, once you're sure, click the "edit this page" button , found on the top of the page, next to the "history" button or at the top of a section you can find also the "edit" button. Then find the area that you found the error in, and correct the error.
Then you should enter a summary of what you did, as an example, if I was fixing a spelling mistake I might type "Typo" or "Spelling error". Then, if the edit applies to only a word or two, click "This is a minor edit", and if you are especially interested in that page click the "watch" button, found on the top of the page.
To make sure you didn’t make any mistakes, click the "show preview" button to check for errors, or click the "show changes" button to check what your modifications are. Finally, when you are sure of your edit, click "Save Page".