I have no idea how to write the second part which should me a critical reflection on how the research has reflected my practice as a teacher.
Is that really what it is? How the research "reflected" your practice? Probably they want to know how it "affected" your practice.
How did it affect your practice? This is about metacognition. You need to reflect on what insights you gained while doing that research. What thoughts came? What questions arose? Based on your process, you have changed as a teacher. Every little thing changes you, so they want to know what effect this had.
By the way, please check out the EF Contributor Page (link at the bottom of the screen). Helping students via essay forum is like pure charity -- something you give of yourself to make a little difference in the world. As a teacher, maybe you want to become a contributor. :))
Does this advice help?