I'll bet the answer to this is obvious, but I'll ask anyway...

I have a few sets of bifold, closet doors in my house. Both sides of one
closet are in alignment and open and close just fine, but they don't
"lock." Let me explain: There is a piece of metal on the outer edge of
each door that the two sides, when closed, are supposed to press against,
thereby holding the doors straight and closed. No matter how I adjust
these pieces of metal, the doors just won't lock and fall open slightly.
What's the trick? Should one be above the other a little bit? In perfect
alignment? How far out from the edge of the door should the metal
protrude? Is this really just a day-long, trial and error session? Help
me surprise my wife.

TIA.
C