Mix together the flour and filtered water in the glass container. (If you do not have access to filtered water, fill a container with water and let it sit on your counter for at least 24 hours. The chlorine, which kills sourdough yeast, will evaporate and the water will be safe for use in your starter.)
Set it on your counter, uncovered.
Wait 8-12 hours. (Do step 1 a few hours before bed and you'll be ready for step 3 in the morning.)
Mix 2 tbsp of flour and 2 tbsp of filtered water into the starter.
Wait 8-12 hours.
Mix 1/4 cup of flour and 1/4 cup of filtered water into the starter.
Notice the pattern? Continue to repeat it (doubling the amount of flour and water at each feeding) until the yeasts from the air and the flour have begun to ferment the flour.
Once it begins to smell like beer (read: fermented) you have a working starter.It may take several days for your starter to "catch". Give it time. Tell it you love it and that it's the most beautiful starter in the world. It's a living thing, after all!
Continue to feed it flour and water. Now is the time to consider buying a gallon-sized glass jar.
Keep building until you have enough starter to make the recipe and have some left over to feed and keep alive for your next loaves of bread.