Thanks Nicolas. I figure it out. I was trying to use the green line as buy signal and red as sell signal. My custom below using EMA 100 to follow the trend. It would be grateful if you have further suggestion.

DEFPARAM CumulateOrders=False
capital = 100000 + strategyprofit
n = capital / close
// --- settings
prd = 30 //Period to Check Trend
rateinp = 1 //Trend Channel Rate %  minval = 0.1, step = 0.1
ulinreg = 1 // 1=true, Use Linear Regression
linprd = 10 //Linear Regression Period, minval = 2
matype = 1 //ma type 0=sma, 1-ema, etc.
// --- end of settings

rate = rateinp / 100
pricerange = highest[300](close) - lowest[300](close)
chan = pricerange * rate

p1 = 100
//trend
masrc1 = average[p1,matype](close)
if ulinreg then
ma1 = LinearRegression[linprd](masrc1)
else
ma1 = masrc1
endif

hh1 = highest[prd](ma1)
ll1 = lowest[prd](ma1)
diff1 = abs(hh1-ll1)

if diff1>chan then
if ma1>ll1+chan then
trend1=1
elsif ma1<hh1-chan then
trend1=-1
else
trend1=0
endif
else
trend1=0
endif

ret1 = trend1*diff1/chan

alpha1 = min(255,(80+abs(ret1*10)))
if ret1<0 then
r1=255
g1=0
else
r1=0
g1=255
endif

iprev=$prev[p1]

$prev[p1] = ma1

IF g1 = 255 THEN
BUY n SHARES AT MARKET
ENDIF

SET STOP %LOSS 10

IF r1 = 255 THEN
SELL AT MARKET
ENDIF