Ok this is how it works, after you beat the final boss, you'll unlock some new stuff that will appear on the title screen such as New Game+ and Lineage and Legacies (which is the Future arc).
When you go to Lineage and Legacies, simply pick a cleared file and you'll start the Future arc right away.
Once you beat Future Arc, you'll be able to save your game which will put you right back in the main game, at the save point right before Lambda, but now you'll retain all the stuff you got in Future arc.
Richard is playable throughout the entire Future arc, but he's gone once you're back in the main game. Though there's still a way to play as him in the main game from getting something in Future arc.
I should note that loading a cleared file doesn't automatically put you in a New Game+ like it did in Symphonia and Abyss. There's now a separate option to start one from the title screen.
In fact if you were to load a cleared file, it would unlock Zhonecage which is the EX Dungeon, but it's highly recommended that you don't go through it until after going through Future arc.
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O brilliant blade of coldest steel, rend the infinite darkness and crush my enemies to nothing... SAVAGE WOLF FURY