The words in Qinyuan Spring Snow are slightly coquettish. Who does Song Zu mean here and how did he become emperor?

Song Zu here refers to Zhao Kuangyin and Song Taizu, and Zhao Kuangyin was the founding emperor of the Song Dynasty. He used to be a proofreader of the Later Zhou Dynasty and was trusted by Chai Rong, Zhou Shizong. After Chai Rong's death, Chai Zongxun became king. Zhao Kuangyin is generous, good at making friends and has many followers. After the young master ascended the throne, he actively cultivated his own power when people's hearts changed. Later, when the Khitans attacked, Zhao Kuangyin led an army to meet them, and then went to see Chen Qiaoyi. The accompanying soldiers wore yellow robes, but he was drunk. Zhao Kuangyin has the ambition to be emperor. After pretending, he led the army back to Kaifeng and seized the position of emperor in the following week and became emperor.