I found these YouTube videos helpful in my understanding (and you might find this lab may be heavily inspired by ElectroBOOM :)
ElectroBOOM [YouTube]
Brushed DC Motors and How To Drive Them
Jeremy Fielding [YouTube]
Ultimate Beginners Guide to Using Electric Motors for Makers and DIY Projects; #068
Electronoobs [YouTube]
Types Of Electric Motors - DC | AC | Synchronous | Brushless | Brushed | Stepper | Servo