Stalls can occur when the angle of attack reaches the critical angle, causing the airflow to separate from the wing and lift to cease. It can happen at any airspeed, flight attitude, or weight, purely depending on the angle of attack.
A spin is an aggravated stall where the aircraft rotates around the spin axis, following a corkscrew path due to one wing being more stalled than the other. To enter a spin, there needs to be a sufficient yaw rate while the aircraft is stalled in uncoordinated flight.
During a spin, both wings are stalled regardless of the direction of the spin, emphasizing the importance of avoiding stalls and spins for safe flying practices.