Shirkuro wrote It's the Musician's Guide to Fundamentals ..
I managed to download a PDF version of the book so as to be able to give feedback, and browsed through it. It seems to cover the same thing as the RCM rudiments series which I studied, did the exams, and then taught to one student. The "rudiments" are sort of like getting all the components together, before you try to learn things like harmony, counterpoint etc. It's like the dentist knowing the names and function so of his tools before he learns to use them.
Here are some differences I see.
The book covers everything in one shot under various topics such as key signatures, major scales, chords, intervals. the course you're taking wants to cover all that (will they do the whole book?) in a period of 6 weeks.
The RCM rudiments likewise had a section exclusively for chords, a section exclusively for scales, etc. However, these sections each had levels marked P (preparatory), 1 (grade 1), 2 (grade 2). You might do P when you're doing grade 4 or 5 practical on an instrument. grade 2 was sometimes done by those preparing for teaching (or a bit earlier). A level might be covered over the period of a whole year or more.
What that allowed is that you got very solid on the fundamental aspect of each thing, before venturing further. At P, key signatures only went up to the ones that didn't have an enharmonic equivalent. Those came at (1). You didn't write them out in C clefs (knowing how to use and relate 4 clefs i.e. alto & tenor for the last two) until (2).
Having all those things in a very short time at all levels makes me feel uneasy. One needs time to solidify things.
If you do have access to the whole book, you could look ahead and get the lay of the land.
The book seems to be very heavy in the names of things.