The site map part of the Design Process aids in visually mapping out the flow of information. The map shows structure (Hierarchy of information) and the linking structure. The site map is a way to communicate to team members on a web project as well as the client. Site maps help evaluate needs for navigation and is a way to visualize the structure of web pages and the site as a whole before doing anything in the way of building pages.It' is the road map of your site to help your visitors. With clearly marked destinations, visitors will know three things: where they are, where they go, and how they can get back to where they came from.
When thinking about your organization, you should think about how visitors might wander through it. You might need to map out clear paths for your readers to use. Do not build pages blindly, have a plan.