Search for your latest new-to-you piece in the SmartMusic library and bring it up. The easiest way I have found to do this is from the Home screen> Find Music> Music Library. Then do a search.
If SmartMusic says it needs to download something say yes. Break out the score and listen away. If you want to check out a part a little closer, bring that instrument up on screen.
Switching instruments may require another small download. I am glad when that happens we have a fast and reliable internet connection so downloads are no problem. And no, you may not hire away our IT staff.
It is good to get a solid idea of what something should sound like in rehearsal before you get to rehearsal. You might want to consider SmartMusic as a tool to help with this.