Hi,

In IContentRepository you have GetReferencesToContent http://world.episerver.com/documentation/Class-library/?documentId=cms/9/72E612B0 wich gives you where a specific content item is being used. To find all content of a specific type you can use IContentModelUsage http://world.episerver.com/documentation/Class-library/?documentId=cms/9/9018F8D5

an example of how to implement the interfaces would be quite convenient

Why do you want to implement the interfaces? To use them you can either use dependency injection or just get them from the service locator, e.g.:

var modelUsage = ServiceLocator.Current.GetInstance<IContentModelUsage>();