Video montage

Whoa- now that might win the broad question of the day award.
In a nutshell
-Import the photos into FCP
-place them on the timeline
-Add transitions

If you don't know how to do any of those just have a look in the manual. Its all covered.

You're kidding ... right?

That's kind of like asking "How do I edit?" Is there a specific problem you're having with FCP? - that's really what this forum is for.

-DH

And of course if you mean montage as in all the photos kinda tossed haphazardly on a table or like they are tacked on a cork board then that is different entirely.