I'm not sure about eating them. Never tried em but for certain you can plant them just like you do cloves and the next year to 3 years will end up with a divided bulb. I have divided bulbs from my garlic bulbils that I plants last fall.
When harvesting your garlic cut the scapes as low as possible above the leaves on the garlic plant. Stick them in water to finish them off. When finished let em dry thoroughly and then rub them between your hands to loosen the bulbils from the umbrel. Plant them in the fall as you normally would the cloves and wait to see what you get next year.
If you only get a round next year just plant it back again in the fall or depending on your zone you can just leave it in the ground and mulch it for overwintering.
If you would like to make seed then thats a slightly different process. You will need to remove the bulbils in order for the umbrel to make seed instead. It wont make both. Growing from Clove or bulbil is like making a clone of the original. Growing from seed will be a different variety. Every seed will produce a different variety of garlic even if they are only slightly different. Like the offspring of anything really.
There's a good link for learning how to make seed for anyone interested.
The photo is just a picture of an umbrel producing the bulbils. Enjoy