If we packed your bread in a paper bag it will keep well in the bag for a few days. Once the loaf is open return to the bag or store cut side down on the board. It will eat well for a few days.
Sourdough bread is naturally mold resistant. Storing in plastic will soften the crust and increase potential of mold forming. However, for freezing it is best to wrap loaf tightly in plastic. It will keep well for a few weeks.
Enthusiastic bread freezers often pre-slice their loaf thus allowing easy removal of desired number of slices. Toast from a frozen for best results.