if you run polyES on any module that has knobs (such as ES), they will be automatically assigned to mod buses starting from the first one. you can use mod buses to control various parameters, such as octave and transpose, and if you use any i2c devices you can also control volume and, in case of txo, waveform, attack and decay.
to select which parameters mod buses control (and the range for each parameter) use this page: https://github.com/scanner-darkly/polyearthsea/wiki/output-parameters-and-modulation
you can also use arc, shnth or a MIDI controller as sources for mod buses. for arc and shnth simply connect them to the USB port and they’ll be automatically assigned. for MIDI, arm recording, then move the knobs you want to use, then disarm.
remember, you can control multiple parameters with the same mod bus, so you could assign one knob to change waveform on 4 TXo voices, for instance!