Beats come in four types: action, reaction, setup, and deepening. A beat can only ever be one type. Most scenes are dominated by 1-2 types of beats, though they can easily include all 4.
Stories are a combination of scene & summary. Even the shortest story contains at least one scene or summary. A scene is when a small span of time is covered in great detail; a combination of what characters say, the actions they take, and any relevant details. A summary is when a large span of time is covered in only a few words.
Once in a while a scene needs something more, a touch of extra emphasis to increase the tension. Usually this means either asking a character to make a sacrifice, or forcing a character to endure and suffer.
Within a scene each character has a goal and obstacles preventing them from achieving that goal. This means every scene contains at least one conflict, if every character is collaborating or competing to achieve the same goal.