When you downloaded the xml file you can copy it in the avatar folder of the game.
In the chinese client it’s “Netease/ty/game/avatar”.
In the CBT client it is usually “MyGames/Revelation Online/game/avatar”.
In the character creation you can load the file, but you have to be on the right character model and gender
(for example: you can’t load a loli character when you chose the normal female).
This is how it looks in the chinese client:
And here the EU/NA CBT client:
You can save and load a preset with the first two options.
I hope this helps. If you still have questions feel free to ask in the comments below.