For the most part there are multiple possibilities depending on your overall network setup and existing IP assignments.
Do you have the User Guide/Manual?
I found this link but the .pdf file would not open for me:
ftp://ftp2.dlink.com/PRODUCTS/DI-LB604/REVA/DI-LB604_MANUAL_1.00_EN.PDF
Try a search from your location. Start with DLink' website and support pages directly.
Watch out for sites that claim to have the manual but try to get you to download something else or pay.
The manual should provide you with more information regarding the blanks (or fields) you need to fill in.
What I generally suggest is that you go through the manual, decide what values to use in the configuration fields. Try with one device until you get it to work. Keep notes and do/change only one thing at a time.
And remember that the QoS settings may provide only limited bandwidth control.