|African violets can be repotted using a good quality soil-less mix formulated for container plants. Keep in mind that these plants do well when they are in a pot that seems small for their size, so do not repot unless it is truly necessary. Move to the next larger size, do not go to a much larger pot than the one it is in now. When you repot, set the plant at the same depth as it grew before, no deeper.
How to repot a bulb would depend on what kind of bulb it is. Amaryllis for instance do well in about a six inch wide pot. If you have forced spring blooming bulbs, you would want to plant them outside rather than try to keep them going in a container.
I'm sorry I can't be more specific for you but I hope this helps you get started.