Generally put 1 cup of water into the instant pot to let it make some steam pressure. I usuall put the broccoli on the little wire platform but putting it the water should be fine. Older models let you set the timer to 0 minutes which is fine too. Unless the stems are pretty thick, by the time the pot comes up to full pressure it’s ok to stop. Also, use the steam release button to let the steam out as soon as it’s time, so the broccoli doesn’t overcook.