First, you will need to download a program called Bluestacks: http://www.bluestacks.com
Then use it to install Clash of Clans by searching it in the Google Playstore.
and that's all there is to it!
Now, to capture screen replays for a website, you will need to SnapzProX - http://www.ambrosiasw.com/utilities/snapzprox/
It is the only decent easy-to-use footage capturing software available for Macs.
You can download a free trial first.
If you want to use it permanently, it costs around £40.