There are two ways to get to a Performance Screen in Metronaut (the screen that allows you to see the score and play it!) and from anywhere in the App where you see Piece information whether Home or Search: You either press the Play/Nauts button (if the piece is already obtained or if the piece is not yet purchased), or you pass through a Piece Detail screen. You can get to the latter by clicking on the Composer icon as shown in the following screenshot showing a simple search result in Metronaut v1.1.0 or above:
The Piece Detail Screen contains detailed information about the piece such as main instrument, difficulty level, available arrangements, your choice of arrangement to play (with a default choice based on your instrument), and also the possibility to Preview both accompaniment audio recording and the music score.
The following screenshot shows a detailed view of the above piece, where you can preview audio and music score by simply tapping the highlighted area.
Note: Arrangement score preview is available as of version 1.1.0 of Metronaut.