Troubles with wireless with WRT54GS router

Hello, I;m having troubles with my wireless connection using a WRT54GS wireless g 2.4 ghz with speed booster router. When i hook up the ethernet from my BRAND new comcast modem, the internet on my desktop works fine. Then when i hook up the wireless, the wired internet on my desktop and the wireless for my Dell laptop (M140) both do not work. I dont know if i hooked it up wrong or if its my router or what.

The way i hook it up is this, theres a yellow wire for my wireless router. Theres a white wire for my modem, they are both ethernet. I hook the yellow wire to the computer from the first hole port of the wireless router. Then, i hook up the white wire from the modem into the wireless router but into the hole that stands alone, or the internet hole. Is this the correct way to hook it up?