Hi
I would like to set my router as a bandwidth manager. Need help to configure the router.
Its depend how your router is configured. If its gateway then simple queues can help you.
OR
you can create a transparent bridge and insert it between your gateway and clients, and create Queues to restrict bandwidth or traffic passing from it 
You can use this transparent bridge as a transparent Firewall also to block unwanted traffic from passing by, and this will not appear in any trace as well 