You can stall a wing at ANY speed if you exceed the Critical Angle of Attack. This is why your flight theory manual is not just for passing a test—it is what keeps you alive in a base-to-final turn.
If you only read one page from your downloaded PDF, make it the page explaining the . Many pilots are taught that "speed makes lift," but that is a half-truth. The AoA is the angle between the wing chord and the relative wind.
Don't spend $150 on a dense textbook yet. Download the PDF. Start with Chapter 4. Understand the relationship between lift, weight, thrust, and drag.
Disclaimer: Always verify that your study materials apply to your local aviation authority (EASA, ANAC, etc.) as regulations vary, but physics is universal.
Unlocking the Skies: The Best Free PDF Resources for Aerodynamics and Flight Theory