Start with the DHT11 sensor, place it on the breadboard.
Connect pin 1 to VCC (5V) on the Galileo board and pin 4 to GND on the Galileo board.
Connect the sensor's pin 2 to both Galileo pin 5 and the diode.
Connect the other end of the diode, and the cathode, to the Galileo board pin 6.
Place one leg of the photocell in series with the 10k Ohm resistor.
The other end of the resistor should be grounded by connecting it to the GND pin or the blue power rail.
Connect the row where the resistor and the photocell meet to the A0 pin of the Galileo board.
Connect the other leg of the photocell to VCC.
Insert the SD card into Galileo's onboard SD card reader on the side of the board.
You can refer to the following schematic as a guide: