[Mediawiki-l] problems editing mediawiki text

[wiki software]

hi
 I have finally managed to install media wiki and am now trying to
upload content in it. The problem that im facing is that im not able
to edit some of the default content that comes with the software, like
for example,

Main Page


Contents [hide]
1 WELCOME TO RADWIKI
1.1 Binghamton University research  wikipedia
1.1.1 Please use the Search to the  left to find a specific topic, or
choose a category below to browse to an  article.
2 TOPICS
2.1  TECHNOLOGY
2.1.1       HARDWARE
2.1.2       SOFTWARE
2.1.3       SUPPORT
3  BU RESERACH NEWS
3.1 Expert on measuring stress  creates guide for researchers
3.2 Isbell named distinguished  professor
3.3 Binghamton University researchers  measure holiday spirit


 WELCOME TO XXXXXX

Only from Welcome XXXXXX its the content im uploading, how do i get
rid of the ones above, the edit option does not allow this, how can i
customize the look of the wiki.

someone please helps me,

Thanks.