In Destiny 2 Season of Arrivals, the hero needs to do some things about the Pyramids. The Pyramids herald the coming of the Darkness, and with the Darkness, a new power. But the absolute chaos heralded by the Darkness and the powers that be do not come until Nov 2020. So until then, the hero has to decide what to each week in the Season of Arrivals before going Beyond Light.
First, at the start of each week, the hero needs to level up.
Then go ahead and get to the Contact mission. At the moment, this is on Titan.