how can I pass them as a parameter to access them using the three square brackets[][][] inside a fuction?

a[10][20] and a[40][50] are fundamentally different things. Remember that array notation is (roughly speaking) just a fancy facade for a pointer. Accessing a multi-dimensional array is the same as accessing a pointer with a little arithmetic. The compiler has to know what arithmetic to use, though. a[] is alright since the compiler can figure it out (it's just a+x) but a[][] is not alright (since the compiler needs to use a+N*y+x but has no idea what N is).

If you want to pass around multidimensional arrays you're going to have to provide more information to the implementation of your function. This can be done manually in C by passing in a pointer and the dimension information as distinct parameters and just doing all the work yourself. It can be done statically in C++ using templates letting the compiler do all the heavy work.

template <typename T, size_t N, size_t M>
void foo(T(&cubes)[N][M]) {
  // you can access `cubes` like you'd expect, sizeof works, etc.
};

int main() {
  char test[10][20];
  foo(test); // deduces to foo<char, 10, 20>(test);
}

You also might consider make a cube struct and then define one or more std::vector's with them. So you can simply pass a pointer to the vector or the vector itself if you like