Sorry to say the huge amaryllis bulbs are a bit tricky to coax into bloom again after they flower. The key is the right amount of moisture the right day length so the plant can experience shorter days and longer nights and a cool temperature while the bulb rests or goes dormant and a warmer temp as it gets ready to make flowers. The easiest method is to enjoy the green leaves on your bulbs now and set the plants outdoors during the summer keeping the soil slightly moist. Then in fall bring the plants indoors and place near a bright window so they can experience shorter days.  Add a slow release plant food such as Osmocote in September to encourage blooms. If the bulb has had a proper rest time and the soil was moist but not wet with good drainage you may see a flower stalk form in the winter. Or it may take two years for the bulb to make another bloom. Think of it as  fun challenge.   From the photo you sent I can predict your bulbs need a few more years of growing green leaves before they will flower. Don't give up as getting them to flower again will be a real celebration of your patience.  Keep growing, Marianne Binetti