In what climatic conditions do savannas and steppes spread on the plains, and in which – deserts?

So, in the savannas there is dense vegetation, it is very warm and humid here. In the steppes there are low-growing grasses, in summer it is warm here, but winters can be quite severe. But in the deserts it is quite hot and dry. The most famous desert on our planet is, of course, the Sahara. It is located in Africa, and to be precise, in the northern part of this continent. It is worth knowing that every year this desert moves about six kilometers towards the south. Most of this desert is uninhabited.