You can say that someone is all at sea when they are in a state of confusion or uncertainty.

For example:

I’m all at sea about these new regulations.

After the news, he was all at sea and didn’t know what to do. 

If you had never seen a computer, you would be all at sea with modern technology.

I tried to do well in this class, but I’ve been all at sea 

since we started.

I’m all at sea in this new job of mine. I’ve never been 

responsible for these kinds of contracts before.

Bill is all at sea because of this calculus problem.

 Can you help him?

Tradução:

All at sea significa estar todo confuso, perdido, completamente desorientado.