Download the Netflix app from the App Store....If your phone is on the same Wireless channel as the Chromecast, you should see the Chromecast logo in the upper right part of the Netflix screen. Click on the logo, and it should list all of the Chromecasts avaiable, then select the one you want and you should see it on your TV.
I found alot of issues with the Chromecast version of Netflix and the Chromecast device that I did not like. Some examples are:
1. No ability to pause, or fast-forward while streaming a move from my iPad.
2. I could shut down my iPad and the Netflix "cast" would still be running on the Chromecast device and my TV
3. It seemed like I had "no control" over the movie whatsoever once the content started streaming to my TV.
Now my oldest son who has a Droid device said he could do all that and more from his Nexus 7. I'm going to try my Nexus 7 tonight. I did read that Google did not implement many features on the iOS platform that they did on Droid devices, but then why would they? iOS is a competitor....