Once you have maximum Karma, travel to the Subterranean and reach the Void Sea . The Recommended Route

You spawn with a green neuron fly in your hand. Delivering this to Looks to the Moon is your primary narrative goal.

Efficiency is critical. Experienced players often use the following "speedy" route:

Head down to Shoreline to deliver the neuron to Moon.

Reach Sky Islands on your first cycle to save time and meet the first Echo.