If you are happy with your current wireless network, the easiest (and best) way to add the TC to your network is connect an Ethernet cable from one of the available LAN <-> ports on the Netgear router to the WAN port (circle of dots icon) on the TC, and then configure the TC to act as a "bridge" on your network.
Backups will occur over your current Netgear wireless network, and you also will have the option of connecting your computer directly to one of the Ethernet ports on the TC to allow backups to occur 3-4 times faster than wireless will allow.
Since you probably don't need another wireless network, you can simply turn off the wireless on the TC.
Another configuration option....although it is more difficult.....is to configure the TC to "join" your existing wireless network. Backups will occur over wireless only, so you could locate the TC anywhere you want as long as it can receive a good wireless signal. It this type of configuration, the TC functions simply as a wireless hard drive.