Hello ,

i do have couple questions about developing a game like clash of clans

i don't know where to start ?

what should i learn to make it happen ? started using Unity3d i do have pretty little experience

should i continue on it ?

is there is a book that could help ?

http://www.gamedev.net/page/reference/faq.php/_/for-beginners-r1

Start here.

I think you already have a premade asset on the Unity Asset Store for that kind (or simillar atleast) type of games.

There are quite some games already made on that principles of gameplay if you will.