// patch
SinOsc c => dac;
SinOsc m => blackhole;

// carrier freq
331 => float cf;
// modulation freq
100 => m.freq;
// index of modulation
0 => float index;

// loop!
while( true )
{
    // modulate
    cf + index*m.last() => c.freq;
    // advance time
    1::samp => now;
}