The traps should always be placed in sunlight as this helps activate the attractant.
The mixture is poured 1/3 of the way down the yellow section & then left in sunlight to attract the flies.
The trap should be placed away from buildings you want to keep the flies from. A Rule of thumb is that the traps should be about 30m apart.
Please do not hesitate to call or write but the operation is a very simple one & very effective.