The aim of the game is to build up your army and your base to attack and defend against other players. Whilst attacking you get the opportunity to plunder your enemies resources ( a certain percentage) and also earn trophies.
The extra dimension to the game is that you can create or join clans, hence the name. Being part of a clan has its benefits. Firstly, it gives you the advantage that you can talk to other members within your clan, either for social reasons or for the improvement of your gameplay. Secondly, and most importantly, your clan mates are able to donate troops into your clan castle for you to attack and defend with.
All the above may sound trivial, but added together it makes a fun and addictive way of passing your time on your iPad, iPhone or iPod.
Apart from having a good time, the heart and soul of Clash of Clans is the obtaining of trophies.
Used to buy buildings and upgrades as well as looking for battles.
Used to build troops and certain buildings and upgrades.