What are some important modules I should install in Drupal if I am going to use it for a news website.
For a news site you're probably, at the very least, wanting:
CCK- gives you the ability to create custom nodes
pathauto- allows the automatic creation of human readable urls
views- very versatile module that lets you create aggregates of content based on rules and restriction
Panels- lets you group different pieces of drupal structures on one page (a view, a node and a search form on the same page)
I think the first step is to get your roles set up properly as to who's allowed to do what etc. And, yes, more information would be much more helpful.
Picxelplay is right, but that said, you may want to check out Open Publish, a Drupal distribution aimed at newspapers and the like.