Tips and recommendations on how to begin modifying example B1 basic

Hi! I’m new on Geant4 and I could use some tips and recommendations on how to start to get familiarized with geant. I figured I could mess a little with example B1 (and other basic examples) but for that I need to understand a little of the basics, such as: if I want to change the detector geometry, do I have to do it in the cc file of the example (in this case,, and then build the modified example? Or are there commands I can run in the GUI itself to modify the geometry there?

_Geant4 Version: v11.2.1
_Operating System: Windows 10
_IDE: Visual Studio 2022 v17.9.7, don’t know specifically the compiler’s version
_CMake Version: 3.29.3

Dear Emily,

I would recommend following the beginners course which happens every year. The recordings, material and code are available in indico, link.