Indesign is not quite the best application for Web Design, as it is a rather a tool for printing (typography) layouts. Its web design capabilities are poor. I would have used Photoshop or/and Illustrator instead.
The web design technique is otherwise: no matter what graphical tool you use for a layout, you should cut the image into pieces and write your self the HTML and CSS codes to insert those pieces into a real web document. Dreamweaver can give you some help in writing the codes, but in the end you have to code almost with your bare hands