Begin with a heap of faith that the wild yeasts will land in the wet dough you set out in a corner of the kitchen. Pray that they colonize peacefully and bubble and alchemize into the promise of bread. Do not fret about the smell. This is fermentation, after all.
After three days expand the starter with flour and water and hope. Leave overnight.
Doubt the results but forge ahead. Coax the yeasties. Tell them, this, This! is what you were meant for. Rise you yeasties, rise!
Add a smidge of baking yeast from the freezer. Do not despair! All is not lost. Only helped along.
It rises. Oh, joy! Knead and let rise again. Bake and be grateful for any extra rising. But do not expect it.
Exclaim in wonder, the fresh loaves so lovely and the smell, why, its heavenly. Sourdough!
Slice and serve your family without apology for the dense bread. Say, If ever we had only water and flour, this bread could still be made with nothing more than the lively air and a hot oven. We will always have bread!
In the meantime, keep practicing.