Tutorials in introductory physics (TIP) are a well known resource for use in third level insititutions for developing students' understanding of physics concepts. However, this resource is only sparingly used at second level. This study presents an adaptation of the approach taken in TIP to enhance the understanding of vector addition of a group of upper secondary students. The results present qualitative evidence of the development of the students' understanding of vector addition. Issues surrounding the application of their understanding to an electrostatics context are also examined. Our results indicate that the approach taken in TIP can improve student learning at second level, and contribute to the small body of literature on this topic.