Hi,
I'm Sumi Jang from Korea. I've graduated my primary school and secondary school in Korea. I'm currently in college outside Korea. I haven't used Slack before, but I can be contacted through that if you need it.
Here are the answers to the questions you request:
1. Yes, I'm a native Korean.
2. No, I haven't.
3. Yes. I'm a college student and recently on a temporary semester-off, so I'm online most of the time.
4. No, I haven't.
If you need any verification for this project, I can take a test with some items you give.
Thank you for your time. I look forward to hearing from you.