Some basic concepts
Basic terms are described,
such as tick (a price change),
control in algorithms, and comment in programs.
The main event when trading on financial markets is the change of price.
This is why tick is an important event that makes the basic mechanisms of MQL4 programs run.
What happens when a new tick comes in?
What actions should the terminal take? This is control that moves to the forefront here. But,
do not forget to comment upon your code.