Maxwell by hand
To really lean anything, one needs to practice over and over, by hand. Here is a complete derivation of the Maxwell source equations using quaternions. Instead of picking the familiar Cartesian coordinates of t, x, y, and z, generalized coordiantes are used with the numbers 0-3.
Copy this over until you can do so without looking at a reference image. Leave your practice sheets around where you work or study. People will presume you are a genius.