mix for sponge with sourdough ?

Pre-ferment may be either sourdough (lactobacillus + yeast) or yeast (just yeast), while sponge is only yeast. Logically, a sponge is always a pre-ferment, while a pre-ferment may or may not be a sponge. A sourdough starter is a pre-ferment, but not a sponge. The historical reason for this was after the scientific discovery and later mass production of baker's yeast, breads lost a lot of quality. Thus, the "sponge and dough" method was devised to improve quality with a method reminiscent of the multiple build "refreshments" of sourdough which had been practiced for a rather long time prior. A bulk ferment is a fermentation period that occurs before dough is divided. For example, you may want to make dinner rolls. While you could make one roll at a time, why not make a dozen, or more? So, you mix up your dough for X number of rolls, inoculate it, then let the yeast numbers grow (ferment) in bulk. After bulk ferment is over, the dough will be divided into your 12 rolls, you'd shape them, then let them proof (final fermentation), before putting them in the oven to bake. Most of this information is freely available on the Internet, have you considered doing Internet searches? Here's a basic bread formula given in "Baker's Percentages". 100% flour 60% water 2% salt 20-40% starter, or 1-5% compressed yeast, or smaller amounts of dry yeasts. Once it's all mixed, then you go through the process of, briefly, bulk ferment, division, shaping, proofing, and finally baking.