I'm frustrated with the way this recipe is written. It may work wonderfully for an experienced sourdough baker, but to someone new to the process it's not helpful at all.
I tried this as the first bread with my new rye starter and, after a complete failure (well, not complete - I turned it into some lovely sourdough rye crackers) I dove in and did more research on sourdough baking. I realize now that what the recipe author intends is for the baker to make a sourdough "sponge" the night before baking. It's too bad the recipe never mentions that word, or I'd have looked into what a sponge was sooner. As directed, I fed my starter the night before but I fed my *whole* starter, not simply taking out a cup then and making a sponge. The steps for doing this are completely unclear for anyone who is unfamiliar with the ins and outs of sourdough breads and really ought to be clarified.
NOW, I have a sponge sitting on my counter and will try again the proper way tomorrow. Lesson learned.