I can only answer for myself and how I knew; for me it was very obvious. They’ve come to me in dreams and in visions. And I’ve actually seen Sekhmet. So I’ve had conversations with a few. I know some other pagans that have had similar experiences. I would imagine that dreams and visions would be the most common way. I know some that have had little more than a sense of knowing that they were being called and didn’t meet with their deity in dreams or the astral till much later on if at all.
Write something about yourself. No need to be fancy, just an overview.