The ONETEP Developers Group are organising a 3-day Masterclass 4-6 September 2024 at STFC Rutherford Appleton Laboratory, Harwell Campus, Didcot, UK. The Masterclass will train participants to apply ONETEP to their own specific problems of interest and to use the Atomic Simulation Environment (ASE) graphical interface to run and analyse calculations with the code.