I want to create a block listing some articles and I want to add a custom scrollbar to that box. So it shows 3 article teasers and then it scrolls but scrollbar is custom design.How can I do that?Thank you in advance.
To create custom scrollbars, you need webkit.
Webkit: http://css-tricks.com/custom-scrollbars-in-webkit/
See the examples and read the documentation on how to do this.
In order to pull your 3 articles, you can use the views modules and create a block views. The views module is hard to explain but you will manage if you take the time to read the doc and experiment with it.