Help me please

 I need to insert this function (extern double BandsDeviations = 2.0) but I have a big problem ... I know nothing about programming, I hope some expert can help me

Thank You

PS: sorry for my bad English

#property indicator_chart_window

#property indicator_buffers 2

#property indicator_color1  Red

#property indicator_color2  Blue

#property  indicator_width1 1

//---- indicator parameters

extern int    BandsPeriodRed=24;

int    BandsPeriod1=1;

extern int    BandsShiftRed=0;

extern int    BandsPeriodBlue=19;

int    BandsPeriod2=1;    

extern int    BandsShiftBlue=0;

double LowerMirror1[];

double LowerMirror2[];

//+------------------------------------------------------------------+

//| Custom indicator initialization function                         |

//+------------------------------------------------------------------+

int init()

{

   SetIndexBuffer(0,LowerMirror1);

   SetIndexBuffer(1,LowerMirror2);

   return(0);

  }

//+------------------------------------------------------------------+

//| Bollinger Bands                                                  |

//+------------------------------------------------------------------+

int start()

{

  int counted_bars=IndicatorCounted();

  int i,limit;

   if(counted_bars<0) return(-1);

   if(counted_bars>0) counted_bars--;

         limit = MathMin(Bars-counted_bars,Bars-1);

   //

   //

   //

   //

   //

   for(i=limit; i>=0; i--) LowerMirror1[i] = (iMA(NULL,0,BandsPeriodRed,BandsShiftRed,MODE_SMA,PRICE_CLOSE,i)-iMA(NULL,0,BandsPeriod1,BandsShiftRed,MODE_SMA,PRICE_CLOSE,i))+iMA(NULL,0,BandsPeriodRed,BandsShiftRed,MODE_SMA,PRICE_CLOSE,i);

   for(i=limit; i>=0; i--) LowerMirror2[i] = (iMA(NULL,0,BandsPeriodBlue,BandsShiftBlue,MODE_SMA,PRICE_CLOSE,i)-iMA(NULL,0,BandsPeriod2,BandsShiftBlue,MODE_SMA,PRICE_CLOSE,i))+iMA(NULL,0,BandsPeriodBlue,BandsShiftBlue,MODE_SMA,PRICE_CLOSE,i);

   return(0);

  }

//+------------------------------------------------------------------+