Complex sentence: Baquedano, the Chilean commander, decided that only one brigade, Lynch's brigade, would march the miles to Chilca and all others Chilean forces would be (re) embarked in Pisco for Chilca only from Lima.
Split into simpler sentences: Baquedano, the Chilean commander, decided that only one brigade, Lynch's brigade, would march the miles to Chilca. All other Chilean forces would be (re) embarked in Pisco for Chilca only from Lima.