I dont know if you mean that you don't know much about the current Congos and Angola or if you mean the Kingdom of Kongo. However, if you have some time and you like reading then you should read about the Kingdom of Kongo and their ManiKongos (their rulers). The Kingdom of Kongo covered significant areas of the current Congos and Angola; in fact the land of Angola was a gift from a ManiKongo to Portugal, so that should give you some idea of how large the Kingdom of Kongo was and how wealthy, advanced and orderly the people of Kongo were. The saddest part is that the Portuguese and later the Dutch with the help of some crooked ass Kongo Chiefs fanned the flames of Civil war in Kongo when they all kept undermining successive ManiKongos. The Civil wars eventually caused the collapse of the Kingdom of Kongo and made the Kongo one of the biggest exporters of war prisoners who were sold into the transAtlantic slave trade.
Interesting reading if you have time and it sheds a totally different light on African civilization. The letters written by one ManiKongo to the King of Portugal about the Portuguese and the crooked Kongo Chiefs kidnapping Kongo royalty, noblemen and other dignataries and selling them into slavery is incredibly sad.