I believe this is more of a grammatical question than a translational one. What I am referring to is things like this in English (using something I saw on Reddit as an example):
Zamenhof Day Duolingo Challenge
I an not a native English speaker but AFAIK such things are normal in English, and most words can work both as nouns and adjectives, so I guess some of the words in the example are treated as adjectives and this somehow makes sense.
But how to translate this to Esperanto? I know that simply sequencing nouns will not work:
WRONG: Zamenhofa tago Duolingo defio
But does this look fine:
Zamenhofa taga duolinga defio
Or would it be better to use prepositions:
Defio por la zamenhofa tago en Duolingo
Or is there a completely different and better way?