First, you'll need to join the Echo Sequence I challenge site. It's located inside the central temple (pyramid) of the Nexus.
Second, find the invisible stones within this challenge. To do this, go right and forward to the edge of the map until you see a stone with a picture of Koda.
Third, jump on the invisible rocks until you see the "Echo Sequence II" challenge. This location is a mirror image of Echo Sequence I. To get the badge, you also need to run left and straight ahead to the rock with Koda's image. Once you do, you'll receive the badge.