If you are using the DLink at home in Bridge mode to connect wirelessly to a router, then you probably just need to give both the same WPA security code.
You can connect via Ethernet cable directly to the DLink and browse to the wireless security settings to create your own personal code.
At competition the DLink is given a personal security code for use only on the Field.
You can also change the DLink to the AP setting if you want to do without the router altogether and connect directly to your Classmate or laptop wirelessly.
You still need a common security passcode though.
You can also follow the
How to Configure Your Radio directions to setup your DLink.