This document describes the development of a web-based courseware applying van Hiele's theory of geometric thinking levels. The courseware is intended to provide differentiated instruction for elementary mathematics students learning about geometric figures. It summarizes key aspects of van Hiele's theory, including the 5 levels of geometric thinking and 5 levels of study. The proposed courseware aims to assess students' current visualization level, provide level-appropriate content through games and activities, and improve students' spatial reasoning abilities. Details are provided about how the courseware interface was developed, including login procedures, a main menu, and rooms targeting different skills.