This challenge was only obtainable during the 10 hours of EA Access before the game was released. This challenge became unobtainable on the 18th of October, 2016, when the owners of the "Early Enlister" copy of the game could access the full game.
As long as you had an EA Access subscription ongoing, you could enjoy 10 hours of Battlefield 1 - online or singleplayer, no purchase required.