In settings you will also find this online help. You can set the language of the app (DE/EN), if you do not want to take the default language of your iPhone/iPad.
Usually I leave the display active, because you don't want to unlock the screen while playing, but this can be change here.
Also as a default, the player continues playing when the app goes into the background or the display goes off. Please change this here how you like it.
Another setting defines what happens when selecting a new song (manual or via pedal), if it starts directly or is stopped.
Additional to the inApp settings, there are two options in the iPhone/iPad settings which may be useful: you could reload the sample songs if you have removed them from the first playlist and you could also clear all your playlists in one go.