a little help please

[comfits.livejournal.com]

this is probably super simple, but how do you use these silly things?  i'm using them on the ends of a cord for a necklace.  i put the cord through the hole, but i can't clamp the thing.  which end do you stick the cord in, how do you clamp it, & how do you get the lobster clasp on.  please & thank you =]