Ableton's official Learn Live series walks through assigning LFOs inside the Wavetable synthesizer's Modulation Matrix, starting with a practical demo of routing LFO 1 to filter frequency and LFO 2 to Oscillator 1's wavetable position. Values can be set by clicking and dragging in the matrix grid or typing them in directly from the keyboard.
A key concept covered here is that modulation sources can themselves be modulation targets, meaning you can route one LFO to control another. This opens up layered, evolving movement that goes well beyond simple one-to-one mappings.
The bit closes with a MIDI source example, using note velocity to drive the wavetable position of Oscillator 1. MIDI and MPE sources plug into the same matrix workflow as LFOs, so the approach transfers immediately to any other external controller or performance input.