Hi Molly. I made a sheet sheet for you.
The instructor (right bar, 3rd icon down) is great for learning the tools.
I recommend trying out all the tools and windows and figuring out how they work one after another. For example make a line with the line tool, then try out the freehand tool, then try out the arc tools, etc. If you ever get stuck, try reading what’s in the instructor window & if that doesn’t work, then ask the forums.
If you want to follow along the tutorials with the same version, then you might consider downloading SketchUp Make 2017.
SketchUp is an extremely cool program! It’s an indispensable tool for making anything in real life because it helps you plan in 3D. SketchUp is great for things like rearranging your room, planning an event, or even designing a building! The applications are virtually endless. When I was first learning SketchUp, I had difficulties too. It seems like there’s always something new to learn, despite it’s simple user interface. I’m sure you’ll figure it out soon though, but it does take a bit of time/effort to become proficient. The things that helped me learn SketchUp the most were the “SketchUp Training Series” on Youtube and the SketchUp Forums. I went to school for drafting too, so that helped a lot. I wish class used SketchUp more though. 
But if you take some drafting classes, then it will help a lot. A lot of the programs use similar concepts & many drafting classes use Sketchup in addition to AutoCAD or something. If you’re motivated enough though, then you can learn everything they teach in class and more from the internet. The information is out there if you’re willing to check it out.