World of Tanks Modern Armor

To get to War Stories, select your server, pass the initial loading screens, at the main menu select 'War Stories' (above 'Multiplayer')

Challenge mode must be unlocked before you can use your personal tanks. To unlock challenge mode, you have to complete all chapters of a single story.

Once challenge mode is unlocked for that story, select any tank EXCEPT the original tanks (2506, Emcha, Resistance, Berliner, Tigre...) made for the stories. Beat all three chapter with your own tank (you can even choose different tanks for each chapter) to unlock this achievement. This achievement will also unlock with the stories in Spoils of War that are one chapter long like Sieben Ritter, The Connoisseur, and Topemkin. (Credit to iDeary 97 for that last bit)

If a tier X tank is used, the following achievement can also be unlocked after one chapter.