John Carlos and Tommie had many meetings before they did the protest. After the race was over and they were on the podium they decided they were going to take their stand and break barriers. Smith grabbed black gloves out of his bag to wear during the national anthem. Smith gave one of them to Carlos to wear on his left hand and Smith would wear one on his right hand.  

As the national anthem played John Carlos and Tommie Smith raised their fists with black gloves on them for human rights. Smith had his hand straight up, but Carlos had his slightly bent in case someone came at him he could defend himself. The whole stadium was quiet. When the quiet ended a lot of booing and yelling started coming down. People were screaming the Nation Anthem and it didn't sound like the National Anthem.

Carlos and Smith got expelled from the Olympics. Avery Brundage gave them 48 hours to leave the Olympic Village. Once they got back to the black community everybody was proud of them. They got their medals taken away but they were not that mad about it.  

John Carlos, Tommie Smith, and Peter Norman after receiving their Medals.

https://www.history.com/news/1968-mexico-city-olympics-black-power-protest-backlash