When first growing your Amaryllis bulbs make sure that there is always a little bit of water just underneath the bottom of the Giant Amaryllis. This will enhance the growth of the stem and flowers. The Amaryllis is a tropical plant and grows best in warm temperatures. 75º Fahrenheit is the ideal temperature for them. Within 2 - 4 weeks you should see the first flowers growing.
While your Amaryllis plant is growing, you can support the stems if they begin to get longer than 15” otherwise the stems may break and ruin your beautiful flower.
3 months after purchasing you will likely stop seeing blooms. This is when you can begin following steps for regrowing your bulbs for the next season! The steps for regrowing your bulbs always depend on your environment and climate zones as well as the condition of your bulb. See "What should I do after flowering?"