If your main router is non belkin you need to contact the manufacturer for support. The wireless equivalent of cascading is called bridging.
Linksys Official Support Using The Wireless G Bridge As An
Which belkin routers support wireless bridging. You can check to see if your router is supported by any of the third party firmwares such as dd wrt that do support wireless bridging. There are two 2 ways to cascade a belkin router to another router. The only two belkin wireless g routers that support wireless bridging are the f5d7230 v6 v8 and v9 and model f5d7234 v1. Wireless bridging works with the following models only. Belkin high speed mode wireless g router f5d7231 4 belkin wireless g router f5d7230 4 belkin 54g wireless network access point f5d7130 belkin wireless g wireless universal range extender f5d7132. This method is officially supported by selected router models only.
Setting up wpa or wpa2 security on the belkin wireless router. You can only set the belkin f9k1110 as an access point. If your main router has the wireless bridging capability you can try to swap the two routers and make the f9k1110 as the main router. Resolving issues encountered while accessing the belkin routers web based setup page. Checking the belkin routers wireless settings through the web based setup page. Checking the belkin routers ip address.
Changing the wi fi password of your belkin router. Most stock router firmwares do not support bridging between routers. This wont work with the setup that you want to achieve since setting the router to access point may need an ethernet cable to connect the two routers. Belkin models supported by dd wrt.