The Essentials of Hands-on STEM Training is a blended professional development programme that equips teachers and master trainers to deliver practical, inquiry-based STEM lessons using locally available materials. Across three immersive days, participants first experience hands-on activities as learners, then transition into facilitation practice. Through design challenges, activity modification, and lesson design tasks, they learn how to implement inquiry-based learning, manage classroom logistics, and sustain practical teaching throughout the school year using tools such as the STEM Box and the PEN Resource Manual. The training is supported by a Learning Management System that includes pre-work, video assignments, reflections, quizzes, and feedback. A final facilitation and logistics module prepares master trainers to confidently plan and deliver Essentials workshops independently. Assessment is continuous and competency-based, with certification awarded upon successful participation and completion of post-training requirements. The programme offers a structured, replicable model for strengthening hands-on STEM education in schools.