This is the autolyse process where the flour is being hydrated with the water.
Add warm water, active starter, salt, and flour to a large bowl. Mix together and allow to rest for 20 minutes. This is the autolyse process where the flour is being hydrated with the water. Typically, you would just add the water and flour together. But to save time we are skipping this and completing the autolyse with the starter and the salt.