The purpose of this paper is to specify your variables of interest. What are your independent and dependant variables? Depending on your research question, you may not be able to list all of your independent variables yet (for instance, if you are doing an exploratory study, it may be more difficult for you to have a clear list). If that is the case, discuss what you think will be your independent variables, based on what you have read/learned so far on your topic. Include what your unit of analysis is.
How are you conceptualizing, operationalizing and measuring your variables? Discuss dimensions, indicators and validity. What are the possible attributes of your variables? What is the measurement level of your variables? Finally, what kind of methods do you think is the best for your research question?