To unlock this achievement you will need to purchase all of the training modules. You purchase them with xp that you will earn throughout the game and there are 9 of them to acquire. They each cost 2400xp, so you will need a total of 21,600xp to purchase them all. To purchase the training modules, you need to go to 'Single Player', 'Agent Profile', then 'Upgrade Shop' from the main menu, or by pressing in game then going to 'Upgrade Shop'.
You earn xp by completing objectives and challenges during missions.