Yel means "Al Saad" street signal. I think it is the fourth signal if you are in "Al Waab" street and Villagio on your left.
Otherwise, her description is absolutely correct.

And regarding the waiting time, yeah it is true that you have to pay 150 QR to start early as in normal cases you may wait for a whole month.

And regarding the school itself, my rating is not more than "Good" (Depends on the driver who will teach you.).

Good luck and happy driving :)