What Does It Mean to Fill in the Troops at the Beginning?

(Please bear with me if I'm a newbie.) As soon as he opened and closed his eyes, Chen Nan came to a city wall from the 996 Fortune News Company. Just when he thought he was in a theater, and before he could recover, the coldness of the rifle in his hand and the giant fireball falling from the sky made him wake up instantly. He had... Traveled through time. (Not brainless) (No system) (No heroine) (Shit pit world)