Hi Issac,
I'm only learning so please take what i say with a pinch of salt...
Slots and slats re-energise the airflow travelling over the wing. As air travels over the wing, the air can be called laminar (not sure but i think it extends 1mm form the surface of the wing) where each air molecule follows the one in front. Until it starts to separate (separation point) from the wing and starts to becomes turbulent. As the AoA increases, the separation point starts to move forward along the wing. Eventually the laminar air flow gets smaller and the area of turbulence gets bigger. Slots and slats, help to prevent this happening by keeping the air flow, flowing over the wing and preventing it from going turbulent.
About stalling, as the AoA increases. The Centre of Pressure (CoP) moves forward towards the leading edge. The CoP is where the lift component acts, think (thrust, drag, lift,weight forces), when the CoP gets close to the leading edge the wing, the wing will be reaching it's critical AoA (usually around 16deg's for training aircraft). The CoP moves sharply rearwards and the wing is stalled, lift is no longer greater than weight, and the nose drops and you lose height.
Im not sure if your book goes in to coefficiency of lift and drag?
The formula for CL is lift=CL x ½ x air density x velocity squared x surface area of the wing. You might be getting confused with camber and surface area? As the only two things pilots can do to affect lift and drag, is too change he surface area of the wing and it's velocity.
I hope this helps in someway?
Andy