Get bar body size + draw horizontal line at 3x distant from bar + pop up alert and draw arrow.

My old indicator show red down arrow as sell signal, and show pink up arrow as buy signal.

Step 1 : When red arrow appear (price might continue keep going up), wait for bearish candle appear.

Step 2 : Compare body size of the bearish candle and the previous last bullish candle, take the 1 that bigger body size. For example, if bullish body size is 20 points but bearish body size is 15 only, so take 20 points.

Step 3 : body size x 3 times = distant. Example just now take 20 points at step 2, so 20 points x 3 = 60 points distant. Draw a horizontal line at 60 points above the candle body.

Step 4 : when price go up touch the horizontal line, pop up alert "USDJPY Sell". And draw blue down arrow at the horizontal line where the price touch it.

Step 5 : Repeat the 4 steps above in opposite direction for pink arrow.

Picture reference at below (please ignore the purple horizontal line because it is draw by my old indicator)

Hope can complete it in few hours. Let me know how many hours u can complete it. Thanks.