Hello everyone, I am now having problems with code that I had written, so I thought to use debugger,but the aid does not give me much information, then I thought I'd ask the community how work this debugger, for example if I have the following code :

While[FreeQ[vistos, {{1, 2, 3}, {4, 5, 6}, {7, 8, 0}}, Infinity] && 
  contador < 15,
 exa = mutacion[Last[vistos]];
 For[i = 1, i <= Length@exa, i++,
  If[FreeQ[vistos, exa[[i]], Infinity] && 
    FreeQ[examinados, exa[[i]], Infinity],
   AppendTo[aux, exa[[i]]];
   ](*end if*)
  ];(*end for*)
 fmaximo = f /@ aux;
 buscaf = Flatten[Position[fmaximo, Max[fmaximo]]];
 If[Length[buscaf] == 1,
  AppendTo[vistos, aux[[First[buscaf]]]];
  aux = DeleteCases[aux, aux[[First[buscaf]]]];
  For[k = 1, k <= Length[aux], k++, AppendTo[examinados, aux[[k]]]];
  ,(* else *)
  For[i = 1, i <= Length[buscaf], i++,
   AppendTo[auxuno, aux[[buscaf[[i]]]]];
   aux = DeleteCases[aux, aux[[buscaf[[i]]]]];
   ];(* end for*)
  minimog = g /@ (auxuno /. {0 -> 9}) ;
  If[MemberQ[minimog, 0], 
   Which[Length [minimog] == 1, minimog[[1]] = 1,
    Length [minimog] == 2, For[b = 1, b <= 2, b++, minimo[[b]] = 2],
    Length [minimog] == 3, For[b = 1, b <= 3, b++, minimo[[b]] = 3]]];
  buscag = Flatten[Position[minimog, Min[minimog]]];
  For[k = 1, k <= Length[aux], k++,
   AppendTo[examinados, aux[[k]]]
   ];(* end for*)
  aux = {};

how to do step by step to see the code I've written, you can do line by line? thanks in advance