Painting as in studying the history or painting, or that of the practice of being a painter? In both cases still it comes to interest which you have, learning and practice. Learning to paint is rather quick, you learn your materials within the first lesson, but also practice is part of the learning experience. A Fine Art historian would study the paintings to learn when, how and why they were painted-the reason behind the image. A painter would want to express a why, a how, and setting to express their visions. Painting can be in any and all media, from actual paint, like oil or acrylic to the style a different media is used like chalk, water color, gouache. To know painting you must want to know why you want to paint, what you want to say through the painting and why the skills would be important to learn. I believe even a historian who studies paintings would have to recognize brush strokes, and the way you learn the purpose for the strokes is by experiencing that movement for yourself. To know paint and painting is to also learn about the use of color, how it blends, compliments and feels beside other colors, textures.
I hope this helps.
And before I move on. When you are done with painting but still have some in the can set it off to the side under a tarp to keep rain and water out of the open cans to let them dry completely then toss in dumpster. Don't throw a paint can away with liquid paint in it, could be violation of clean water act and could also cause dumpster to be rejected by disposal company
If it is the latter, you may start by finding a media you want to try since painting involves a lot of medium , watercolor, oil, acrylic, pastel, ink, etc. There are a lot of free resources online. There is a facebook page called "Streaming art video" where a lot of professional artist will showcase how they do a painting on Facebook live video. If you want a more structured approach to learn painting, you may consider New Master academy - "https://www.nma.art/". Although it is a paid platform (you may start by having a monthly subscription to have a try first ), but the tutorials by all those porfessional artists on it are very informative and I believe you will learn a lot from it.
I hope all these information are helpful to you. :)