Question about flushing before harvest

So I've been reading about flushing during the last 7-10 days of flower and am a little confused.. do I cut out all nutrients and start watering with plain water the last 7-10 days or do you actually run 3x the amount of water to the size of the pot the whole 7-10 days every time the plant needs watering? OR do you just flush the first time with 3x amount of water and then just water with plain water the rest of the time up until harvest?

yea i wanna kno that same thing except mine are in the ground