Can you connect a PC this way?

I have a Cisco DPC3010 modem and a Nergear N600 Wireless Router. I would like to connect one PC directly to the modem using the USB port and have the ethernet cable run from the back of the modem going to the wireless router for the other computers in the hose can this be done? I was not sure if you can use only one port at a time or both. Thanks, Jason