On the face of it, gain staging couldn’t be simpler: you ensure that you feed an appropriate level from the first stage of your signal path to the next, and repeat this from the second stage to the third… and so on, all the way from your instruments, mics and preamps to the final stereo mix bus. By ‘appropriate’, I mean an ample level, which ensures a healthy signal-to-noise ratio (the difference between the wanted signal and the noise floor), while leaving enough headroom that you needn’t worry about whether the signal might be clipping.