Well for starters, I typically check wikipedia first: https://en.wikipedia.org/wiki/Fennel
And from my experience I can tell you that fennel yields many parts of its plant for culinary use. The ubiquitous part of the fennel is the bulb as seen in the picture. The stalks are removed and discarded, the base is cut to remove any oxidized or rust colored pieces, the bulb is cut in half, and finally the core is removed because of its woody texture that never cooks out. Sometimes the outer layer is removed if it looks damaged or rusty. From here the bulb is julienned or small diced. If serving raw in a salad, a mandolin can shave it so thin that the texture is no longer noticed and the flavor of slight licorice is added.
Fennel is cooked like onions, slowly sweated to soften and will caramelize. Left in half, the bulb can be braised. The fronds can be minced and added as a garnish. The seeds are harvested and toasted to use as a spice. Lastly the pollen can be collected and eaten too.
For some, fennel tastes too much like black licorice or anise and has no part in their diet. I like the light crisp refreshing texture. So I hope you have a chance to add fennel to your diet once in awhile. See you on a Sunday.