This thrust, low, high combination may feel a bit awkward to you at first, and you might feel that there is no power behind your strikes. Don't worry! With continued practice it will become very natural to you and later these strikes will be fine tuned so you can deliver with massive power.
What's most important about learning this challenging combo early is that performing these three strikes while taking two steps helps your mind to overcome the obstacle of coordinating your hands and feet to operate independently, but still in proper timing with each other. Whether you are throwing punches or delivering strikes with a stick, your feet must move in order to place you in a good position to attack, but they must also be timed with the hands so that you can be set to deliver with power. However, your hands will easily deliver strikes faster than your feet are moving, so timing is key.
Finally, this is a great combo that acts as a setup for a powerful strike to the leg which you will learn later. Once you master this combo, you will have already cleared a challenging hurdle, so don't give up!