Nope, not that simple, at least for some of us. Chromecast does not play well with some routers and the extent of this problem appears a mystery. Google does have a page showing specific router models with known problems but my late-model, popular Netgear router is not there and Chromecast refuses to do business with it. The router and Chromecast see each other and even talk, but that's it -- I never get to the "Ready to Cast" screen.
Meanwhile, when Chromecast during installation sets up a temporary hotspot for itself, it trashes my default network connection, requiring me to do a Windows repair diagnostic or reboot each time.
Google's FAQs and troubleshooting are unhelpful, with half a dozen or more fairly technical "fixes" to my router configuration, which anyone who hasn't done a manual router config would likely not understand. I do understand the advice, but suggested configuration still leaves the device. Maybe I should replace my expensive, high-end router with another model that MIGHT work so I can plug in a 35-dollar gizmo. Don't think so!
Moreover, it becomes clear as I work the problem that Chromecast will not tolerate a moderately secure router. VPN? Nope. Proxy DNS? Probably not. Firmware firewall via NAT? Not a good thing, Chromecast says. And yet other roadblocks. But I realize that even I got this thing working, I'd be surrendering the level of security I wish to maintain. Must I compromise my secure network for this little device? Not unless I'm crazy. Hey, Roku and Apple TV and other solutions don't make you do that, but of course Google is big time into the information-collection business. Thus this gizmo, for me, remains a brick. It was also a Christmas gift that I've already spent too many hours trying to make work.
Nice idea, badly executed. Which, when you think of it, is more and more the Google style. But it might work for you without compromising your own needs, so if you'd like to buy a nearly brand new one complete in the box, let me know and I'll offer you a nice deal.