You will need:
Big Pot with lid
plastic plate to float inside (should be slightly less diameter than the main pot)
3 kg fresh lavender (stems and flowers)
3 litres of distilled water
1 kg of ice cubes
glass bottle to store
Put lavender greens into the pot, press it well, you can also cut it to make sure more lavender material to be in the pot.
Pure distilled water on top, put on medium fire, and wait to boil.
Put fire down to minimum, put plastic cup inside, and turn lid upside down. The best is to have it slightly conical, so the water can drip from it into the cup.
Put ice cubes on top of the lid, to help water to be condensed faster and drip into the cup.
Change ice cubes regularly and check water, empty the cup when full.
You can also put kitchen towel between pot and lid, to avoid steam coming out.
This is distillation process, and after you finish and put lavender water in the glass bottle, you will see layer of the lavender essential oil on top.
You can use this water as face mist, linen freshener, ironing water.
Note: Make sure you DO NOT HAVE ALLERGY on any of essential oils mentioned above!!!