1. What is column 2 (How is it measured?) asking?
Answer: whether the variable was measured using a Likert-scale, questionnaire, observations, blood sample, etc.
2. What is column 3 (Natural or manipulated?) asking?
Answer: This is asking if the variable was natural (e.g., sex, height, race, marital status) or manipulated by the researcher (e.g., caffeine, morning time versus evening time, answering in cold room vs. warm room, etc.).
3. What is column 4 (Qualitative or Quantitative?) asking?
Answer: You'll need to determine if the variable is nominal, ordinal, interval or ratio.