There you go:

BBperiods = 20   //periods to calculate Bollinger Bands
LookBack  = 50   //min BB gap in these last bars
MinWidth  = 2    //max percentage of distance between the two bands
BBwidth   = BollingerBandWidth[BBperiods](close)
C1        = BBwidth = lowest[LookBack](BBwidth)
C2        = BBwidth > BBwidth[1]          //Contraction ended
BollUP    = BollingerUP[BBperiods](close)
BollDOWN  = BollingerDOWN[BBperiods](close)
L1        = close CROSSES OVER  BollDOWN
S1        = close CROSSES UNDER BollUP
CondL     = C1[1] AND C2 AND L1
CondS     = C1[1] AND C2 AND S1
IF CondL THEN
   DrawText("Buy",barIndex, low - range*2,serif,bold,15) coloured(0,128,0,255)//135
ELSIF CondS THEN
   DrawText("Sell",barIndex, high + range*2,serif,bold,15) coloured(255,0,0,255)
ENDIF
RETURN

Placing SL & TP at the end of your code or just after the entry doesn’t make any difference, unless you use different values for the two sides.

For position size management you can add this at the beginning of your code (just after DEFPARAMs):

////////////////////////////////////////////////////////////////////////
// DrawDown calculation + LARRY WILLIAMS' formula for size management
//
ONCE Capital     = 10000  //set your initial investment
ONCE LotSize     = 1      //start with 1
//------------------------------------------
//       DrawDown calculation
ONCE MinPoint    = Capital
ONCE MaxPoint    = 0
ONCE MaxRU       = 0
ONCE MaxDD       = 0
IF StrategyProfit <> 0 THEN
Equity        = Capital + StrategyProfit
TempProfit    = PositionPerf * PositionPrice / PipSize
TempEquity    = Equity + TempProfit
MaxPoint      = max(MaxPoint,TempEquity)
DD            = MaxPoint - TempEquity
MaxDD         = max(MaxDD,DD)
//------------------------------------------
//       LARRY WILLIAMS' formula (+margin)
MinSize       = 0.5                   //Minimum lot size allowed
Margin        = high / 100 * 0.5      //Margin required 0.5%
Risk          = 5                     //Risk per trade 2%
TempLotSize   = max(MinSize,(Equity * Risk / 100) / (MaxDD + Margin))
LotSize       = round((TempLotSize * 10) - 0.5) / 10   //only 1 decimal digit allowed
ENDIF
//
////////////////////////////////////////////////////////////////////////

then use LotSize to trade the calculated lots.
Make sure in your code you are not using any of the above variable names.

YOU asked about the SL & TO and I replied

YOU asked me to provide the code for risk management and I posted the code.

Was tour account hacked and you never posted it?

DrawDown calculated by ProBackTest can’t be known from within a trading system, it’s reported on your screen so that you can take note of it only, so it needs to be calculated by the TS itself if you plan to manage position sizing and risk management on it.

As to SL and TP, well… that dipends on your likings, it can be fixed (number of pips) or dynamic (according to bars recently formed), or based on ATR (Average True Range) or other indicators.
TP, Target (or Take) Profit, is often calculated multiplying SL by a factor (1, 1.5, 2, etc…).

Fixed SL (valid for both Long and Short trades):

SET STOP   PLOSS   50    //SL = fixed number of Pips
SET TARGET PPROFIT 150   //TP = 3 times SL

SL calculated on the lowest Low (for Long trades) and highest High (for Short trades) in the last N bars:

N       = 5                  //5-bar LookBack period
Factor  = 2.5                //TP factor (multiplier)
LongSL  = lowest[N](low)
ShortSL = highest[N](high)
LongTP  = LongSL  * Factor
ShortTP = ShortSL * Factor

SL calculated on the ATR (valid for both Long and Short trades):

Atr = AverageTrueRange[14](Close)
SET STOP   LOSS   Atr
SET TARGET PROFIT Atr * 1.8

As you can see, PROFIT and LOSS both require a difference (or range) expressed in price when SET. They can also be preceded by P if you prefer to set them using Pips, % if you prefer to use a percentage of the price or $ if you prefer to use a fixed amount of currency.