Most large flower bulbs, like amaryllis, hyacinth,and narcissus already have their flower buds and future leaves formed in the bulb. All they need is moisture and proper temperature to grow. The food supply they need is already stored in the bulb. Good light helps, without it the leaves and flowers will be pale. Forced bulbs are often discarded after blooming. This is due to less than ideal growing conditions during forcing. I kept a dozen of last years' paperwhite bulbs, put them outside, fertilized them, and gave them a resting period. They looked about normal in size. I planted them late in the fall, all I got was lush greens, not even one flower.
Wishin, in my opinion it is a good idea to keep the garden bulbs in the garden, and bring their flowers in, even if they last just for a couple of days! Forcing bulbs, is for the novelty of having flowers out of their normal blooming season.
Masoud