At its best:
Fill each hyacinth glass with water to just below where the bulb’s base will sit, then put the bulb in place. Make sure it doesn't touch the water, but sits just above it. Place the glass in a cool (below 10°C), dark place for six weeks for roots to form.
Once the main shoot is about 7-10cm tall, move the glass into full light and watch the flower gradually develop.
Turn the glass around by a half-turn every day, to prevent the plant growing towards the light and toppling over. Top up the water as necessary.