Okay, you can know the principles inside and out, but it won't teach you how to start the car and shift gears.
Every kid knows enough from TV, video games, and riding a multi-speed bike what "shifting" is. Turning a key does not require a driver's ed course. And yeah, learning the systems on paper did teach me about driving a stick shift. I learned how the clutch literally disconnects the engine from the transmission through the throw-out bearing actuated by the clutch pedal. This allow me to use the gear shift level to move the shift forks, changing synchronizers connecting the input shaft to different gear sets in the transmission (or direct to the output shaft, as common in 4th gear of a 5-speed).
That came from your [friend's dad] giving practical advice and you sitting in the car developing the muscle memory that allows you to change gears without thinking about what your feet are doing.
His advice was more tips for timing and pedal feel. It helped, but it was like 10 minutes tops.