External MediaWiki
MediaWiki is a web-based wiki software. To learn about how to use MediaWiki you can take a look on the user documentation. Especially the help pages that describe how to navigate and edit pages in a wiki are a good starting point to get acquainted with MediaWiki.
This SSELab service provides an external wiki, i.e. the contents of the wiki are visible to anyone but are only editable by managers and members of the project. The external read-only pages of a project using this service can be accessed over the public project pages.