Dang ... what do they mean?

Dative = indirect object of a verb.
Accusative = direct object of a verb.
Nominative = subject of a verb.
Genitive = possesive pronoun.

Could someone please give examples of the usage of the above in simple sentences. ? They have dogged me for quite a while.
I appreciate that they are vastly different in German, nevertheless I would like an explanation in English, if you would be so kind. TIA.

Dative: We sent him a present.
Accusative: We sent him a present.
Nominative: We sent him a present.
Genitive: This is my brother’s car.

Thanks Jamie.