I have a few aponogeton bulbs in my aquarium and you just set them there. Some of mine floated so i had to work awhile to get them to set on the gravel. Sadly only one of them grew, but it grew huge. I have a few lily bulbs to and all of them grew. Hope this helped!
-Willy
I hate to be sticking in like this, but maybe this question will be helpful to others - I have dwarf lilies, but there are about six plants sticking out from one bulb, if I separate them will they grow new bulbs?