Had a good supply in 2020. I took it every day for months. I had 210 doses, legitimately prescribed. I never got sick though I was in close contact with countless nbrs. of positive patients for that entire year.
There are multiple sites with instructions. You need grapefruits, lemons, and tonic.
One site here first one to pop up on search.
https://peoplesworldwar.com/home-recipe-for-hydroxychloroquine/