Herbal tea for metabolism with witch hazel

I would like to have more precise information on the preparation of this herbal tea: “1-2 g of chopped leaves or 1 teaspoon of bark powder in a little water. Boil a cup of water, leave to infuse for about 4 minutes, filter, pour over 150 ml of boiling water, leave to infuse for 10 minutes and filter again. ” Does this mean that the water in which the witch hazel has been filtered for 4 minutes must be filtered and thrown away? Subsequently on the freshly filtered witch hazel I have to pour new boiling water and, after an infusion of 10 minutes and after having filtered it, it is only this that should be drunk. It’s correct? Last question: how long should I take the herbal tea? Thanks for your help