For the indicator to appear correctly on the DE40's 5-minute chart, set it to overlay mode.
Variables: Variables are declared to store the high and low points of the first trading hour.
Draw box:
The box representing the range of the first trading hour is drawn in gray.
First trading hour range:
The code checks if it is the first trading hour (9-10 am). If so, the high and low points are stored.
Fibonacci calculation: Based on the range of the first trading hour, the Fibonacci levels 1,61, 2, 2,61, 4,61 above and below the box are calculated.