To earn this achievement, the game asks you to enter the "Training" mode at least ten times.
In order to earn this achievement, you must do the following:
When you start up the game and reach the main menu, highlight "Training" and select it.
The controller select screen should come up next. You can choose to be either on the left or right side, it doesn't matter.
Once that's done, the character select screen will come up. Select your characters, it doesn't matter who it is at all. I remember using a variety of characters for the first or eight times, then used Bison/Juri as my team, with Akuma and Ogre being the enemy team in the last two times.
Chose your stage, doesn't matter which at all. To make it easier though, just select Random.
Once the match starts, you can exit the match and go back to the main menu and repeat all the steps I mentioned above. However, to make it faster though, I recommend RareWhiteTRASH's advice from above and just go back into the character select screen, then re-entering with the same teams you used before.
Once you did this the first time, repeat the above steps nine more times and once the tenth match of the "Training" mode starts up, the achievement should unlock. It's an easy achievement, but also time-consuming. However, it should take between ten-thirty minutes, which really isn't long at all.
Have fun and good luck!