Terrain Osc Modules don't have freq inputs or any tuning settings, just a couple of inputs for "X" and "Y", each with knobs that control Gain and Offset. You can't get them to output any sound unless you are moving these knobs, so, an LFO seems to be the obvious choice to connect to the X and Y inputs. When you do that, the frequency of the LFO defines the pitch of the oscillator, and different waveforms define the timbre of the oscillator. So, to be able to "play" these oscillators, you have to "play" the LFO.
By sending the MVC's Freq and Gate Outs to the Freq and Gate inputs of the LFO, then setting it to External (Ext) Frequency and to Retrigger, each key press will trigger an LFO with a frequency that corresponds to the note. When this is sent to the Terrain Osc X and/or Y input(s), it will make it sound that note.
If you check the screenshot, you can see this in different ways: OSC A has two LFO's, one for X and one for Y, but their frequencies are the same (taken from MVC)- btw, choosing different waveforms causes changes in the timbre of the Oscillator, but not in pitch. All regular Waveforms produce a steady pitch, only the S&H one will produce a more chaotic result. OSC B has a single LFO for X and Y, also from the MVC, but, by using the freqMult module, you can tune in in relation to OSC A. In this case, a value of 0.5 makes it play an octave lower, while 2 would make it play an octave higher and so on…
Play around with the settings for X and Y and hear the differences in sound (shame there's no Mod input for these), and also with the waveforms. I'm using the "Terrain Select" Module, as it allows you to choose between the 5 different algorithms that are also available as the individual Terrain Osc modules. Once you find the algo you like, using the single "terrain" modules should save up a few cycles.
I'm enjoying the sound of these oscillators, they can be extremely soft and creamy, with very subtle changes in harmonic content when you play with the X and Y knobs.
Another trick I learnt yesterday, by mistake, is to connect the EG output to the KeyF input of the filter, then setting it to max (think it's 200). With long release times, and high resonance values, you get a really nice stepped filter sweep
Scope is one of the few remaining pieces of software where mistakes can be very rewarding. 
