These are good questions to have. Since no one has responded so far, I will give it a go.
First of all, the general understanding of exposure is that if your data is in a linear space, increasing exposure means doubling the values and decreasing, the halving. This means that it is different from lifting the mid-tones on a curve (and what to do with a curve also depends on whether it is perceptual or linear).
A good way to start is to understand how curves and basic tools work. For that you have
– RawPedia, which is available in multiple languages
– Getting Started - RawPedia
– https://www.cambridgeincolour.com/ for more general information