The easiest way is to lay out a prototype on paper. Also, there is dedicated software for making wireframes, such as a cloud-based
Mockingbird (you can use it directly in the browser), or
Axure, an app to be installed on your desktop. They are used by professional designers to design and test websites, applications, and programs. But you can easily prototype a one-page website on a piece of paper.
Prototypes have two main purposes: