This is a Positive Edge Triggered D flip flop constructed using 2 D latches, and the Latches are made up of Transmission gates and Inverters.
The Input on the top is the D input.
The Input below is the Clock input.
Try varying the D input, you will see the working of a Latch (during Negative Clock Level only).
When the clock goes from Low to High you will notice the input reflected on the LED.
