Having trouble coming up with something to draw? No worries - while you'll eventually learn how to start from a tiny seed of a thought and gradually nurture it into a complex concept to explore through design and illustration, it's perfectly fine not to be there just yet.
For now though, here's an idea that might interest you.
When I was a kid, this group named "Junkyard Symphony" would come to our school and perform for us - they'd grab a bunch of random garbage and out of it, would create the most complex, intriguing musical pieces (at least to my eight year old brain). Today, we'll do the same - though fortunately, ours don't have to work, and nor do they have to be played in front of an audience.
Design an instrument using the kinds of objects you'd find in a junkyard. Everyday things, forgotten things, one man's trash is another man's treasure. You may want to start with an existing instrument and figure out how to swap out its tailor-made components for whatever scrap you can find, or create something entirely new.
Ellipse Master Template
This recommendation is really just for those of you who've reached lesson 6 and onwards.
I haven't found the actual brand you buy to matter much, so you may want to shop around. This one is a "master" template, which will give you a broad range of ellipse degrees and sizes (this one ranges between 0.25 inches and 1.5 inches), and is a good place to start. You may end up finding that this range limits the kinds of ellipses you draw, forcing you to work within those bounds, but it may still be worth it as full sets of ellipse guides can run you quite a bit more, simply due to the sizes and degrees that need to be covered.
No matter which brand of ellipse guide you decide to pick up, make sure they have little markings for the minor axes.