Mix 2 cups bread flour
½ tsp soda
1 tbsp sugar
1 tbsp dry yeast
2 ½ cups very warm water
stir well now add
1 tbsp salt.

Loosely cover and set for 3 days, stir once in a while.
It can now be kept in the frig.
When you use a cup of starter add 1 cup warm water ½ cup flour and tsp sugar mix well let sit again.
Note if it turns pink in the frig throw it away, start again