How do I use the LFO as a 3rd Oscillator?

Just patch from the KB PITCH output on the ARP/SEQ module into the RATE input on the MODULATION module. Then patch from the WAVE output in the MODULATION module, to the NOISE input in the MIXER. Bring up the NOISE level knob in the MIXER section and then user the RATE knob in the MODULATION module to tune the frequency of the LFO as an oscillator.