Your eyes adapt and your monitor lies. The scopes are the objective truth of your image. You only need to understand four, and each answers a different question about your shot.
On the Color page, click the scopes icon (top-right) to open the panel. Use the menu inside it to switch between Waveform, Parade, Vectorscope and Histogram.
The Waveform plots brightness from bottom (black) to top (white), matched left-to-right to the frame. Keep detail off the very floor and ceiling to avoid crushed shadows or clipped highlights.
The Parade shows red, green and blue separately. If a neutral part of the frame has the three channels at different heights, you have a color cast — line them up to balance. This is the single most useful scope for correction.
The Vectorscope shows color as direction (hue) and distance from center (saturation). The diagonal skin-tone line is your friend: healthy skin of any tone falls along it. More on that in fixing skin tones.
The Histogram is a fast read of how tones are spread from dark to light. It is less precise than the waveform but good for spotting clipping at a glance.
The RGB Parade. Find a neutral grey or white area in the frame and adjust until the red, green and blue traces sit at the same height there.
It is the diagonal indicator (around the 11 o'clock position) that healthy skin tones of every ethnicity naturally fall along. Lining faces up to it is a reliable way to keep skin looking natural.
Watch the Waveform: keep your highlight detail below the top line and your shadow detail above the bottom line. Anything flattened against either edge has lost detail.