Your dough should be soft and elastic - almost sticky-to allow the yeast to perform perfectly. So gently mix in the flour surrounding the yeasty part, and go on doing this to the dough until it forms one even mass. It will be sticky at first and the moist parts will stick to your fingers, so keep dipping your hands in the dry part of the flour and sprinkling dry flour on the damp places. The proper action is a gently rocking action which should leave the sides of the bowl relatively dry.