Sometimes a whole field of chamomile can be harvested with the right weather and conditions, sometimes not. 2018 was not a good chamomile year in Yorkshire.
Most of these herbs are wild crafted, e.g. Lime flowers from Epping Forest or Lemon Balm from my garden.
Infuse in boiled water for 5-10 minutes in a nice clean teapot or infuser, drink well before bed time.