I am now in the process of making herbal tinctures and will share the process with you.
First of all you need to do a LOT of reading and studying before you choose to spend a lot of time making this stuff. There is a lot to learn and the web is a great beginning. Books are next and finally a trip into the field to get a one on one closeup view (I happen to be fortunate as I am surrounded by hundreds of acres of Ohio forest and field) In the city you will be better off buying your product dried and packaged in one pound units . . . Mountain Rose Herbals or Frontier brand herbals are good and reliable places to buy from. Amazon prime will get you free shipping from Frontier.
Gather only naturally clean, off road herbs away from chemicals and read about what to do with them . . . a simple and direct way to caring for your personal health without fretting over health insurance and huge out of pocket expenses, especially for chronic illnesses (which western medicine sucks at curing anyway)