Defining FLIBE as a target in Geant4 can be challenging, especially for users struggling with the complexity of the software. The TestEm11 example defaults to G4_Si, which may not be suitable for FLIBE. Users are encouraged to refer to the provided documentation on defining new materials from elemental compositions. Understanding the process of material definition is crucial for accurate simulations. Mastering these steps will enhance the effectiveness of particle transport simulations in Geant4.