Hi, Jackie, and thanks. I primarily prefer pencils/charcoal sketching and digital art. (Portraits and graphic design/illustrations, respectively, often with a surreal/mythological theme.)
I've heard of, but not familiar with the Great Courses series. I"m not a teacher, but I'd say don't stress about specialized supplies. I started when I was a kid, with just crayons and pencils, and whatever paper I could get my hand on. While good materials do make a difference, the real difference comes in observing and practice. I was lucky to have good art teachers in grade school and high school to give me a good foundation, and none of them put emphasis on the materials over practice. Draw, draw, draw. A lot. Learn the different techniques, how to hold the brush, how to apply the different strokes for different textures, look at the light and contrasts, etc, look at the forms. A great artist can create with the most basic tools, because it's in the fingers and hands from practice. Hand-eye coordination is a big part of it, too.
You'll find yourself hitting highs and lows, there's a lot of struggling to get it. But with practice, there will be times when you'll suddenly "get it". But have fun with it, too.