Foundation

Foundation is the foundation of make-up, and it's what we're going to work on, no matter what effect we want to achieve with our overall make-up. Choosing the right foundation is important, because there are many different types: fluid, mineral, compact... And there are many different shades, so it's important to know your skin tone to avoid a mask effect.
To begin with, you need to know if your skin can tolerate foundation. Some skin types find themselves "rejecting" the product only after a few hours. This results in an unpleasant "pack effect" that's difficult to rectify when you're at work, so be careful and try it on for size. The first step is to find out what type of product you can tolerate, and then look for the right color.
Neither too light, so as not to look like a wax doll, nor too dark, as this will give an unpleasant effect of failed UVs. When testing, don't opt for the back of the hand (traditionally used), as your face is often lighter than these extremities. Depending on your tan, opt for the inside of the wrist.
In any case, don't forget that store lights are very different from natural light, so go out and check that it's right for you.
As for coverage? Well, that depends on your objective. Depending on whether you're looking to even out your skin tone, hide some redness or correct scars, you'll opt for more or less density.
Last but not least, a complexion isn't just made up on this basis, and isn't a "single color". The pros don't hesitate to vary intensities to give the face more relief. Yes, this is contouring. Or bases...