I believe my petco has 2 different kinds as well. one is in a light blue package the other is in the yellowish package. I got the light bluish.
I had 6 bulbs. One of them was an onion plant but it rotted within a few days to a week. One was a dud and now about the other 4.. What i did was put them half way in the substrate and within a month you should see roots starting to come out. After the roots have been out for about a week i then bury the bulb fully into the substrate and let the plant grow.