When the chapter starts, leave the crashed ship and head towards a small, greenish structure straight ahead. Inside there will be a corpse, on which you can perform a Data Buffer, and right behind those there's a growth, with which you can interact. After completing both of those activities, pick up the tablet lying on the ground, from which you will be able to learn a few interesting things.
When you reach the communications antenna, before activating the panel in front of the building with the antenna, you should first investigate the building itself - approach the doors and open them by activating the control panel (this time your ally won't have to cut through it). Inside, on both walls (to the left and right from the entrance) there are messages written in blood, which can be checked, and a note which can be found on the desk.
Get to the "Delta" building, where a monitor, on which you will be able to check a few things associated with the world of the game is. After reading through everything, you should check the map located directly behind the computer, as well as the subway lines scheme to the right of your current position.