You have to apply a gradient to the stroke before you can change the gradient stroke options.

The Classroom in a Book explains this. You've simply misread.. or missed.. something when reading.

You have to apply a gradient to the stroke before you can change the gradient stroke options.

After all, what should the options do if there's no gradient to adjust? Granted Adobe could have made them automatically apply a gradient to the stroke, but that may be way too intuitive for Adobe.