When you talk about the South Russian Government, we're talking about people who lived in the southern part of Russia a long time ago, back in 1917 to 1920. At that time, there was not just one government ruling over all of Russia, but many smaller governments trying to gain power.
The South Russian Government was one of those smaller groups trying to gain power. They were made up of different people who wanted to rule the south of Russia, including soldiers, politicians, and regular people who were unhappy with the current government. They wanted to create their own government that they thought would be better.
The South Russian Government had a leader named Anton Denikin. He was a military man who wanted to fight against the government in charge at the time, which was called the Bolshevik government. Denikin and his followers fought many battles against the Bolsheviks, but in the end, they were not successful in getting the power they wanted.
So, while the South Russian Government was a real thing, it doesn't exist anymore. The group wanted to have power over the south of Russia, but the Bolsheviks and other groups were stronger and they were not able to achieve their goals.