Sibelius Player plays, but won't Show.
What do you mean by 'tweak'? Sibelius isn't a DAW and Play isn't a synth.
You choose sounds by naming staves and control the volume, pan and effects in the mixer. Third party play engines and sound libraries may well have more controls built into their interface, but not Play.
You choose sounds by naming staves and control the volume, pan and effects in the mixer. Third party play engines and sound libraries may well have more controls built into their interface, but not Play.