Basically you get to the mission, you go to the platform marked, and once stepped on, you activate the mission. After that you have a limited time to use Parkour moves to reach the statue on the other side of a very large space with a lot of obstacles in the way – I found a really good youtube video that helped a lot in understanding what to do and how to do it. Will embed this video below.

Easiest way is to share this youtube video which showed how the Parkour obstacle course that seem to be the weekly mission actually works: