Hello,i would like to create a k2 plugin that can extend the extra field type (a list of city), basically i need a city list type in extrafield and the dropdown in item forms...can you suggests me steps that i should do ? working queries with k2 is simple.. but working with the API is quite difficult since i don't find API documentation/WIKI

Anyone have the idea ? a help from senior k2 developer would be appreciated... it's kinda hard to learn k2 extension development since there's no wiki/api/developer guide... please help