Project-based multimedia learning is a teaching method where students acquire new knowledge and skills by designing, planning, and producing multimedia products. It has seven key dimensions: focusing on core curriculum, making real-world connections, extending over a significant time frame, allowing student decision making, encouraging collaboration, incorporating various forms of assessment, and having students create multimedia end products. While it provides benefits like engaging students and connecting learning to the real world, it also requires extra time, technical skills from teachers and students, and infrastructure to support multimedia creation.