At the beginning of your end step, you may pay {2}{R} and sacrifice a nonland permanent. If you do, reveal cards from the top of your library until you reveal a nonland permanent card. Put that card onto the battlefield and the rest on the bottom of your library in a random order.
Dreamshaper Shaman can be sacrificed to pay for the cost of its own triggered ability.
If there are no nonland cards remaining in your library, you just randomize your library and continue playing.
While resolving Dreamshaper Shaman’s ability, you can’t pay {2}{R} more than once or sacrifice multiple permanents.
You can’t pay {2}{R} and not sacrifice a nonland permanent, or vice versa. The cost must be paid in full or not at all.