You'll get a meaningful introduction to graphic/visual design concepts while developing a much firmer understanding of design principles — primarily by practicing with real projects (which is the true key to improving your skills). You'll get regular feedback from a mentor on your project work, and you'll Skype with them during the course as well. By the end of the course, you should have a much stronger sense of your own design skills and what you'd like to focus on from there if you want to proceed further (we have additional courses on UI/UX, as well as more intensive options like this bootcamp). Take a look at some past student work in Design 101 from one of our students here.
If you don't already have basic knowledge of design tools like Sketch/Photoshop/Illustrator, we have intro units that cover the basics there, and you'll gain further proficiency with those tools through the project coursework.
You can read more about the format of the course here.