As the other educator stated, you will want to develop a central thesis for your paper. South African apartheid is a large and complex topic, and your thesis will help you find a focus for it. Think about what you would like to prove or disprove about this topic or a unique point you would like to make.

If you are having trouble coming up with a thesis, I would suggest conducting some basic research into this topic and see what catches your interest. You can start with a historical approach by reading a book like The Mind of South Africa: The Rise and Fall of Apartheid by Allister Sparks. This is an expansive historical analysis of apartheid. If you don't have time to read it all, start with the table of contents to pick out just the most relevant chapters. Or, for a more personal but limited window into the subject, pick up a memoir such as Trevor Noah's Born a Crime or Ahmed Kathrada's Memoirs. Movies like The Power of One, Skin, or Cry Freedom may also provide some ideas for the focus of your paper.

Once you know what you want your paper to focus on and have come up with your thesis, you will need to conduct further research for your paper. As you search for sources, look for a variety of secondary and primary sources. Looking at old newspapers and other documents on file with the National Archives of South Africa is a good place to start.

As you gather your information, you may find that it supports your thesis or possibly refutes it. Be open-minded and willing to adjust your thesis to fit your findings if needed.

One good place to start on your research paper is developing a strong working thesis.  A good thesis statement offers insight or an assertion about your main idea and has three or more supporting subpoints. 

Since you did not include many particulars about the scope or requirements of the research paper, I am going to suggest a possible avenue of research that would be both literary and historical in nature. 

Consider researching the literary works of Nadine Gordimer.  A critically acclaimed author from South Africa and a Nobel Prize winner in 1991, Nadine Gordimer writes of the harsh realities of apartheid.  I highly recommend looking at "Once Upon a Time" from the collection Jump: And Other Stories. This story is written as an almost reverse fairytale, concerning her views on apartheid in South Africa.