To earn the "SEND A MESSAGE" trophy in Detroit: Become Human during the chapter "CAPITOL PARK", you must first break into the CyberLife store and free the androids before deciding how you are going to send a message to the humans. At this stage you must choose mainly pacifist actions at each interaction point in the area in order to get this trophy. If you end up with a violent protest you'll get this trophy instead:
Pacifist actions in the second half of this chapter are fairly easy to work out as each interaction point has binary options. Pick the least violent course in each case until your Pacifist bar significantly outweighs the violence bar. Note that you can smash the windows containing androids across the road from CyberLife without incurring much of a violence penalty. Assuming you managed to pull off a peaceful protest, you'll get the trophy when you reach the flowchart at the end of the scene.