hi bro,
i can answer u as that is my profession.....im in a freight industry.
a custom broker is an agent who does custom declaration and clearance.
for eg, if u want to import a product from us to sin, and the freight forwarder that handle this freight do not have an office or representive here, they will not be able to do custom clearance.
so for this case, u need to appoint an agent in sin to do the clearance. This is what they mean by custom broker.
so if u have appointed ABC as the custom broker. the freight forwarder from us will ship the shipment into singapore and notify ABC when shipment arrives. ABC will than takes the docs from the freight forwarder and proceed with the custom declaration and clearance. once that is done, ABC will than send the shipment to your door.
clear enough?