"The red house has no windows."
Translation:Das rote Haus hat keine Fenster.
Nominative is used for the being who performs the action. Accusative has relation to the direct object. i.e: I have a laptop (the laptop is the direct object in the sentence... it is "what" you have.). Dative is used with the being on what the action is performed. i.e. I told her (her is "whom" you told). And genitive shows the owner of something i.e. Jacks car (the car belongs to Jack). That's basically it but you should study each case deeper anyways.