The start point is The Pass of Paddra... There are two gates here, both are located in the southwest portion of the map - There is a crystal gate along the west edge of The Pass of Paddra, and the shiny gate is at the very south of The Pass of Paddra. But first, jump up two ledges, open a treasure cube for 'Encounters' Gate Seal (enables Time Reversal in AF200 Oerba), jump up one more ledge, talk to Noel for a Live Trigger: (Yeul said that if you change the future, you change the past. But what exactly does that mean?), then run to the encampment in The Paddraean Archaeopolis to talk to Hope. Before entering the camp a scene will play, after which talk to Noel for another Live Trigger (I met another girl with the same name and face as Yeul from the future. What could it mean?).
Chocolina doesn't have anything new - she sells the same stuff under special as in AF010 Yaschas Massif timeline.
Talk to Hope for a scene, and then for a Live Trigger: (How should you interpret the images shown by the Oracle Drive? You decide to ask Hope.), then try leaving for another scene, and finally open the Live Trigger Cube in the tent. Ascend the metallic slope next to Hope's tent. At the top reveal a concealed treasure sphere with R1 for 600 gil . To the right of this, look very closely for a tiny invisible image of an item. Press R1 to uncover it, and then collect the Mysterious Artefact .
Grab a chocobo and depart for The Pass of Paddra. You know the area that was covered in searchlights in the AF010 Yaschas Massif timeline? There's a high elevation north of this area, which you can reach by jumping with the chocobo and holding Circle to float for a while. Ignore Bridget's request for the quest, and instead claim the treasure sphere with a Unicorn Horn .
Now walk over to the crystal gate in The Pass of Paddra along the west edge of the map and use a Wild Artefact to activate the gate which unlocks AF300 Augusta Tower . While still in the Historia Crux, choose to go back to AF01X Yaschas Massif.
Walk over to the shiny gate to the extreme south in the dead end of The Pass of Paddra. Examine the gate, answer "Yes." and the Mysterious Artefact changes into the Illusionary Artefact that activates the very gate you've examined. This gate leads to AF??? The Void Beyond timeline.