Yes, the colour wheel! Back to basics is how we know everyone is on the same page! And you will want this for some future classes...So, open up to a sketchbook, or grab a piece of paper and grab the following colours of paint: a red, yellow and blue. With these three colours - known as the primary colours, we can typically mix any colour we want. And, I don't want any cheating here.
So, lets first create our secondary colours by mixing our primaries: blue+red = violet, red+yellow = orange, and blue+yellow = green
And, from there we can make our teriary colours by mixing our secondaries: blue+green = blue-green, blue+violet = blue-violet, ect. Continue until you have completed your wheel.
Yes, some of the colours don't look fantastic, and some might even look a little muddy. That's why some people go out and buy their different colours instead of mixing; and you can adjust your mixing ratios to get the colours more clear and bright. And, you will find that, for example: different blues with the same red will give you different purples...maybe some less muddy than others. The differences are subtle here in my example below, but there are different nonetheless...you can see them better on my paper than the scan.