If your challah rolls turned out dense, it's likely you didn't allow the dough to rise as long as it needed. Typically, the dough needs to rest about 90-120 minutes during the bulk fermentation stage (first rise). However, the rise time can vary depending on your environment. Make sure to go by how the dough looks visually (until doubled in size) rather than by the time limit. Pro tip - Allow the dough to rise in a bowl that is roughly the same size as the dough will be when it doubles in size. This helps you visually see once the dough has properly risen.