I may not be understanding your question well, because this should be a relatively straightforward thing to research online. I'd start with South African History Online (a reputable public history site), specifically this section: http://www.sahistory.org.za/article/history-apartheid-south-africa/. If you want more depth, Saul Dubow's book Apartheid: 1948-1994 is a concise history of the apartheid era in South Africa.