How to calculate depth dose profile in a solid box using geant4?

I have created a geometry of a concrete hollow box, placed a point source inside it. I got the Edep plot, now I need to calculate the depth dose profile in it.

I see extended example TestEm2,4, and 11 but I got bogged down seeing the enormous jungle of code. My understanding so far is, I need to access longitudinal and radial depth of the detector. Then need to get dose= edep/mass in each profile. Then show it in a histogram.

I need instructions whether my way is right and how can I do it simply.

Please do help, I got stuck here for a long.