Certain features of this wiki, like editing pages and receiving an e-mail for changed pages (page change notifications), require that you login. In order to be able to login, you should first register. See the registration page for more information about registration/login.
Make sure you are logged in to the wiki. Click the 'Edit this page' pencil-icon on the upper right of any page to edit that complete page. The small edit buttons on the right (beneath a paragraph) let you edit just the section of the page above the edit button. You can practice using the wiki on the playground. See the syntax page for information about the syntax to use when writing/editing pages. See the registration page for more information about registration/login/editing.
If you're logged in, you can subscribe to page changes and/or namespace changes (namespaces are more or less groups of pages) by clicking the envelope-icon on the right. Once you have done so, you will get an e-mail each time the page changes (or any page within the namespace changes). Note that you don't get an e-mail if you changed the page yourself. You can unsubscribe by clicking the envelope-icon again and subsequently unsubscribing.
Searching something on MN Wiki is easy: just type your searchword(s) right behind the last slash of http://wiki.mn.wtb.tue.nl/ in the addressbox of your browser and the search engine will show you the results in the display window of your browser.