How you've played the game up to this point doesn't hugely matter, but Markus will need to be alive and have escaped Jericho when it was attacked. After 'Crossroads', him and his people will regroup in a church, where you'll address them with a plan. Choose 'Revolution' instead of 'Demonstration' to organise an attack against an android camp.The attack has to be carried out successfully in order to receive the trophy, so be prepared for an intense series of QTEs and fast decision-making. If it helps, lower your control difficulty beforehand. When you reach the camp, complete the QTEs as they appear and command your people to charge or cover you at intervals. Repeatedly choose 'cover' until you reach a tower with a soldier in it, and Markus is laying on his back. Here, tell one group to charge and one to stay.Next you'll reach a heavily guarded section with 3 groups to command. Tell the two in front to charge, and the one beside you to cover. Now just keep completing QTEs until you've liberated the camp.

Liberation Video Guide

Credit to PowerPyx for the video.