Ok, well...What is it that you need help for, if you already realised that the
track fader sets the export level?
Recording in 24 bits there's no need to drive the level higher than around -12 dB (peaks maybe a little higher), if you're sending stuff for someone else to mix.
Inside SONAR the the signal is 32 bit floating point, which in practice means it doesn't clip (audibly). When you export, you need to check the signal levels, otherwise you get clipped audio.