How to make homemade vermouth

How do they make dry vermouth?

Ingredients

1. 1 teaspoon coriander.
2. 1/2 teaspoon chamomile.
3. 1/2 teaspoon fennel seed.
4. 1/2 teaspoon nigella seed.
5. 4-6 fresh sage leaves, or 1 teaspoon dried sage.
6. 1 allspice berry.
7. zest of 1/2 orange.
8. zest of 1 lemon.