In order to build a T flip-flop from a D flip-flop, all you need is a D flip-flop and an XOR gate. Convince yourself that the circuit shown behaves as a T flip-flop...
You may have noticed that when you press the push button Clk the T flip-flop changes sometimes several times the outcome.
Mechanical key switches create a lot of electronic noise when shifting. In that way it can happen that the flip-flop sees this as several rising edges and switches accordingly. This behavior is called "contact bouncing".
In next step you will see that you can build all classes of flip-flops with just D flip-flops.