Select
Training in the Main Menu, then go to
Free Training, where you'll be headed to the Character Select screen. You can select whatever characters you want to, and the costumes doesn't matter as well.
After that, you'll have to play in the
Free Training during 1 hour, which you can be idle at any time, just make sure your controller doesn't disconnect, otherwise your game will be paused.
The achievement tracker does work in this game, so if you leave the mode before the 1 hour, you'll be able to see how much time you have already played.
Keep in mind that the tracker will update only after you've left the mode and most important,
the achievement will only pop once you've left the Free Training.
If you have any questions, feel free to ask me.