Editing Feast upon the Word is very easy.
Simply click on the edit tab at the top of the page. Alternately, if a page is divided in sections you can click on an edit link within the page to edit just a single section of that page. Either way you will come to a page with a text box containing the editable text. You edit by simply changing the text in that box. It is as easy as that. Complete your edit by writing a short edit summary (a short description of what change you made) in the small field below the edit-box labeled Summary. When you've finished press Show preview to see how your changes will look. Then press Save page.
To experiment, please do so in our sandbox, not here or on any of our other pages.
It should go without saying but just in case . . . please do not vandalise the information on Feast upon the Word.
You can also click on the "Discussion" tab to see the corresponding talk page, which contains comments about the page from other users. Click on the "+" tab (or "edit") tab to add a comment.
Generally speaking you won't need to know any special formatting codes to edit. Just type in plain text. Occasionally though you may want to do something more, like add an image, put something in a table, or create a link to another page. If you want to do anything like this you will need to read about the wiki markup.