Start by connecting the LCD screen to the Galileo board. To do so, connect the VCC pin of the LCD to the 5V port of the board. Then, connect the LCD's GND to the board's GND pin. Connect the SDA and SCL pins accordingly. You can see the board's SDA and SCL pins labeled as such.
Here is a picture of how the final configuration looks:
Once the configuration is finished, insert the MicroSD card into the Galileo board and connect it to the Ethernet.