I fixed it, basically any class that has drawing has to be in a Layer (that wasn't the case in 'anotherClass') and that Layer has to be in a Scene. Also that Scene needs to be active or running -> mainWindow.RunWithScene(scene);
I'm planning on doing some tutorials of CocosSharp registering all my process from learning CocosSharp to the release of the game. I'm registering all I do and learn while making the game. When (and if) I start the blog I let everyone know here.