It is generally advised that if you already own an Amaryllis and you want to get it to bloom for Thanksgiving or Christmas that you cut back on the watering and light 10-12 weeks before the time you want it to bloom. What we're doing is artificially producing a dormancy period that will result in flowers when we want them instead of when the bulb is ready to send another flower stalk out.
For recently purchased Amaryllis bulbs you're suppose to plant them, give them a good watering and place them in a warm and sunny area to bring them out of the dormancy the grower put them in.
Sometimes you'll encounter an Amaryllis bulb that just won't cooperate with you. You can plant it, water it place it in the sunniest and warmest window in your house and get nothing. That's the case with the Amaryllis bulb in the photo above that came from an Amaryllis kit I bought on clearance after Christmas. Since last December the leaves you see have probably only grown and inch and the roots haven't done much of anything. It spent the spring and summer outdoors with my other Amaryllids and got the same treatment as them but didn't grow. I talked to it, cajoled it, watered it, gave it sun, gave it shade, gave it water, fertilizer and even threatened it- but it wouldn't grow.
As far as I can see there isn't anything wrong with the bulb and it won't grow and flower because it isn't ready. Today I pushed the leaves aside and noticed that there is a new leaf trying to emerge, perhaps by time I go into a retirement home it will be ready to bloom.
Here's a video I made showing you how to pot an Amaryllis Bulb.
and one showing you how to pollinate an Amaryllis flower.