How do I mix colors?

There are entire books and courses of study devoted to this question. Needless to say, I can’t even begin to scrape the surface here. Assuming you’re already familiar with the color palette of pigment, acrylics mix well together. I usually mix up just as much as I need at a time. With a little patience, you should be able to achieve the color you’re striving for. Just remember acrylics tend to dry a bit darker than what they appear to be in liquid form. Best to try a test on some scrap paper first.