It is not advisable to use this outline form for your language study plan presentation. The reviewers will be assessing your conversational language abilities in written form. Therefore, the information must be presented in coherent and cohesive paragraph formations. The presentation only reflects ideas, but does not reveal much about your pre and post study processes at all.
I will start to prepare for the academic year by pre- reading the course material and research
This is not language related so you can remove this mention in totality when you write the study plan in essay form.
You do not need to respond to the "Why?" question in this essay because it is already obvious why you will be studying English and Hangul as a Korean student. The reviewer wants to know the "how" instead to show the seriousness of your application. The more familiar with Hangul you are, prior to coming to Korea, the more you can prove this by showing even a low scoring TOPIK certification from a testing center in your home country, the better it will be for your application.
What is missing from this essay is actually how you plan to improve your English language skills prior and upon arrival to Korea. These are the 2 mandatory languages that you need to be fluent in or at least, have a working knowledge of the language , upon your arrival in Korea. Being a foreign student in a strange country, you will have the opportunity to improve both language skills during the first year of your stay. Try to highlight both languages in your learning path if you can.