Mixing colors is fun, meditative, and it can be very satisfying. Many color mixing instructions have you making systematic color charts, with small swatches of each color. They look great, they make you feel like you've accomplished something, and they are useful for reference.
|Shades (dark) and tints (light) of Permanent Green Light|
Another way to get to know your colors is to choose one color, and mix it with white and colors that are adjacent to it on the color wheel, or "analogous colors". Also mix it with different versions of the same color. In the following video I start with turquoise out of the tube. I mix it with another turquoise (deeper, darker Pthalo Turquoise), as well as white, green, and a couple of yellows. Try this with any color.
You can try out color combinations in your sketchbook in a non-systematic way. Here is a video in which I put together colors in a kind of 'mood board'.
If you are just beginning a painting practice, I recommend getting as many paints as you can afford. Start with at least a few high quality paints, such as Golden, and supplement with more budget-friendly paints. Include, if possible, two different versions of each primary color: red, blue, yellow. Here is a little article on Color and Paint, which you can download for reference. It includes color recommendations.