Fourth set of orders: Getting harder to make recommendations, more ships will land on planets, settle them, load colonists on ships that came back to your homeworld, send them to the closest/largest planet you have found. You may have encountered races at this turn, send them a message, make friends or not.
At this point, the worlds you have found and the races you have encountered should start to dictate a strategy to you. You need to develop the planets around you and defend them. It is up to you how you accomplish this.