Delta Froakie?

I know its in the Marsh but how exactly do I get it? And what do I have to do with the campfire?

Go back in time using Tesseract then go to the far bottom left and use Heart Swap on the Manaphy Statue next to the trees. For the campfire in the jungle, push the strength boulder that is a little north from the campfire onto the fire and you’ll find a delta.