For a new entry you can either:

Click "My Blog" at the bottom and then the link that says "Post New Blog Entry"

or

"Create Content" at the bottom and then "What's New" from the content type menu

then:

1. Give it a title in the "Title" field
2. Enter your content in the "Body" field
3. Click "Submit" near the bottom of the screen when you are done

To remove a news story/blog from the homepage:

1. Click the title of the story to display it in full on the screen
2. Click the "edit" tab
3. Scroll down to the "Publishing Options" link (right above the "Submit" button). Click it and the options will expand
4. Click the green arrow in the box for "Promoted to front page" so that it disappears
5. Click the "Submit"

It will still be saved and in your "What's New" box listing, but should no longer be on the centre of the main page.

I'll have to show you how to put pictures on the page.