1
general::
Also, clue up. Give someone guiding information, as in It's time someone clued us in on what's happening, or I hope they clue us up soon. This expression, which uses the verb clue in the sense of "inform," is sometimes put simply as clue (as in I'll clue you? this isn't going to work). [Colloquial; mid1900s] Also see NOT HAVE A CLUE.
American Heritage Idioms
2
general::
Phrase(s): clue someone in (on something)
to inform someone of something. • Please clue me in on what’s been going on. • Clue in those guys before it’s too late.
McGrawhill's American Idioms And Phrasal Verbs