Biology question:Explain the principle of "heterozygote advantage"?

if you are aa for sickle cell anemia then you have that disease. if you a AA you wont have sickle cell and you are also very likely to get malaria. however if you are Aa for sickle cell you are a carrier so u don't technically have sickle cell but this make you immune to malaria.that is why sickle cell will most likely always be around because people in africa want to be Aa for it because it is an advantage.