Let me say right from the start that I am not a measuring kinda guy when it comes to my bread. I go on feel, so I’ll try to give an idea of feel as I go. We start our sourdough bread making with a starter culture. This may be purchased, received as a gift from a friend, or made from scratch. I recommend using kefir milk whey, or indeed, just whole kefir milk as a starter, but there are lots of ways (haha) to start a starter.
As a rule of thumb, 4 cups of flour plus our starter will make one loaf.