Once you have loaded up the game I suggest you complete the training you will snag yourself some extra money for doing so.
Once you have completed the training you will return to the home screen, you will notice a menu up the top of the screen. Make sure you are on garage and hover over your first tank.
Next you will want to press (X) and select packages.
You will then notice that there are some upgrades here to be purchased. Just select the first package that requires you to pay for it by hovering over it and pressing (A)
The achievement should then pop up.
I hope this helps guys. :)