I think you are gonna need to get a bit more specific. Are you asking how the coding works? It uses if then, Boolean, and logic statements.
IF 'AHU Occupancy' THEN
START 'AHU #1',
ELSE
STOP 'AHU #1'
END IF
You could write the sentence as,
If AHU Occupancy is on then start AHU #1 else(if not) stop AHU #1.
This code would start and stop the ahu based on the occupancy timer.