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How to prove a Double CNF SAT is in NP

So I've been stuck trying to figure this problem out for a while. I've looked on wikis and all over stack exchange but I'm really stumped. This isn't my best subject, so any sort of explanation would be AMAZING.

The Double CNF SAT problem is given a Boolean formula in CNF determine if it
is satisfiable with every clause having at least two literals that are true.
Show that Double CNF SAT is in NP.

I'm really not confident in these SAT, NP problems. I know that NP is the class that consists of problems "verifiable" in polynomial times. So is my goal to show that a double CNF SAT can be verified in polynomial time? If so, how would I do this?

Thanks for any contributions/help