How to close positions or orders?

Like when after sell order is triggered I like to close Buy order if any order has been executed and when buy order is triggered, I like to close Sell order if any order has been present.

Can’t understand where to put close trade code and also how to use closetrade code in mql5. I don’t want any stop-loss and take profit methods and tickets all that. I want simple direct method.

#include <Trade/Trade.mqh>

input double Lots=0.01;

input ENUM_TIMEFRAMES Timeframe = PERIOD_CURRENT;

input double Step = 0.04;

input double Maximum = 0.2;

int parabolicSarHandle;

int barsTotal;

CTrade trade;

int OnInit()

{
parabolicSarHandle = iSAR (_Symbol,Timeframe,Step,Maximum);

barsTotal = iBars(_Symbol,Timeframe);

return(INIT_SUCCEEDED);

}

void OnDeinit(const int reason)

{

}

void OnTick()

{

double val [];

CopyBuffer (parabolicSarHandle,0,0,2,val);

int bars = iBars(_Symbol,Timeframe);

if (barsTotal != bars)
{

  double close0 = iClose(_Symbol,Timeframe,0);


  double close1 = iClose(_Symbol,Timeframe,1);

if (close0 >val [1] && close1 <val [0])
{

  Print (__FUNCTION__ ">Buy Signal");

  trade.Buy(Lots,_Symbol,0,0,0,"SAR BUY");

  barsTotal = bars;

} 

else if (close0 < val [1] && close1 > val [0])

{

  Print (__FUNCTION__ ">Sell Signal");

  trade.Sell(Lots,_Symbol,0,0,0,"SAR SELL");

  barsTotal = bars;

}

Comment ("\nParabolic SAR[0]: ",DoubleToString(val[0],_Digits),

          "\nParabolic SAR[1]: ",DoubleToString(val[1],_Digits));

}

}

After trade.Buy execution, I want to close Sell order of the same and when trade.Sell is executed, I want to close Buy order automatically.

How do i do it?

Like trade.CloseOrder(trade.Buy) or trade.ClosePosition(trade.Sell) ?

When and where and what to write?