raksta, ka ...

A standard answer to "What's up, man" ("zup, man?") might be "Nothing much." or "Not too much."

bet no otras puses :)

"What's up, man" - without context doesn't make too much sense.

I didnt understand what he meant,
what did he say?, and what does it mean? what should my answer be?

Perhaps your best answer is, "What??"