It's a 50/50 chance they will grow. Just sit them on top of your substrate and wait, don't get too impatient, give them time. If the bulbs start to rot then they need to be thrown away. But IMO if they don't rot, I'd let them sit there for quite some time. I have a beautiful Red Tiger Lotus that is getting really big that I started from a bulb. I can't remember how long it took to start growing but it seemed like it took a couple of months.