You stack 'em.
If you are a perfectionist like KJ (and his Momma) this part can be tricky,
getting the crusts lined up just right.
Put them in a bag. We've found it easiest to put 4-5 in a quart size freezer bag together. You could also put them in individual ziplocks and then use those bags to pack lunches, too.
Then, let them freeze. We just pull out what we need in the morning before school, unwrap from the press'n seal, put in a bag or sandwich container and it is thawed by lunchtime.