Turning Nouns into Adjectives in English is very simple and we do it all the time. One way is the prepositional phrase: "the end of the week." This is actually a development of Late Latin and it comes into English from the French: compare: fin de la semaine. But any prepositional phrase will do in English, and often we can express the same or very similar adjectival relationships with different prepositions: "the end for the week" or "the end to the week" would make equally clear sense. Thus, "the road to Rome" tells you which road. The "message from George" similarly tells you which message. The fact that these expressions really just use a preposition to make a noun into and adjective can be made clear with some other examples: "the love of god" means the same as "divine love" or "the love of a mother" means the same as "maternal love." The genitive case in Latin is the most frequent and flexible way to do the same thing. And this sometimes works in English too: "the message from George" could easily be "George's message" and "divine love" could easily be "God's love." You must remember, however, that IN LATIN prepositional phrases are NOT used as adjectives; they are adverbial, modifying verbs and verbals.
The second way to make to turn a noun into an adjective is Germanic in origin and it depends upon word order: if you put a noun in front of another noun it becomes an adjective. Consider: "the driver of the bus" = "the bus driver" or "the road to London" = "London Road." In Latin, the equivalent expression will use the genitive case: "the bus's driver" or "London's Road."