Complex sentence: Initially Mello's expedition experienced a storm but survived and successfully sailed up the Pearl River delta towards Guangzhou before the end of July, being promptly confronted by a Ming fleet led by Ke Rong and Wang Ying'en, which proceeded to fire warning shots at the Portuguese.
Split into simpler sentences: Initially Mello's expedition experienced a storm but survived and successfully sailed up the Pearl River delta towards Guangzhou before the end of July. They were promptly confronted by a Ming fleet led by Ke Rong and Wang Ying'en, which proceeded to fire warning shots at the Portuguese.