Can I stream to my android phone and to Chromecast plugged into my TV?
Yes, both.
When you first plug your Chromecast into your TV you have to attach it to your wireless network. You can use the Chromecast app on a phone or tablet or the Chrome browser plugin on a PC or laptop to do this. Just make sure the device you are setting it up from is on the same wireless network you want to attach the Chromecast to.
Plug it into your TV and the Chromecast will walk you through the set-up. It's pretty straightfoward. Once your Chromecast is configured it broadcasts its presence on your wireless network so that it can be picked-up by other devices (with the appropriate app / browser plugin installed).
When you open a compatible app on your phone or tablet, or browse to an enabled website, Netflix or Youtube for example, you will see the Chromecast icon
on the screen (or in the top-right browser window corner). Tapping or clicking the icon will display a list of available Chromecast devices. Select the device attached to your TV and your device will be temporarily paired with the Chromecast. Once connected, select the video or program or service you want to "cast" and set it going. (Usually once it has started the Chromecast will take over the running of the program so you can use your device for other things).
You can have multiple Chromecasts in the same household, connected to different TVs, and in that scenario you'll see a list of them when you tap/click the casting icon.
It's all pretty simple once you get used to it. Currys are offering free delivery at the moment if that is of any interest?