Complex sentence: After resupplying the 2nd Brigade with food and ammunition, De Négrier advanced to attack the Guangxi Army, which was occupying a strong defensive position at Dong Dang, close to the Tonkin-Guangxi border.
Split into simpler sentences: After resupplying the 2nd Brigade with food and ammunition, De Négrier advanced to attack the Guangxi Army. The Chinese were occupying a strong defensive position at Dong Dang, close to the Tonkin-Guangxi border.