I see the strip on the bottom as a simple mixer. You hook every oscillator onto a channel in the mixer, send the mixer output to the VCA. The little buttons just link together the parts of the mixer.
If you wanna listen to osc 1+2+3, push the buttons between those oscillators in the mixer.
My AS modular has 2 VCO's, 2 EG's, a multimode filter, comb filter (very strange analog BBD delay thingie that distorts and warps whatever comes through it), ringmodulator, a couple multiples, Modulation controller (cutdown versions of LFO, noise and a small vca in one single module), 2 4-input mixers, VCA and MIDI/CV converter that also contains an LFO and 5 outputs where you can route aftertouch or any other midi parameter into the modular and 2 CV outputs. It looks and sounds fantastic.
I totally want the RS200 3x8 sequencer too, it is modelled after the moog modulars sequencer, and has amazing possibilities. But it's very expensive, costs half the total modular system alone.
They have a moog-cloned bode frequency shifter too, which costs the same as the sequencer. Very crazy module that one.