Draw the level over time instead of setting one number for the whole file. Points are placed in seconds and decibels, and the line between two points is the ramp that gets applied.
Reading the curve
The horizontal axis is the length of the file. The vertical axis runs from +12 dB at the top to -60 dB at the floor, with a rule every 12 dB and a solid line at unity.
A curve with no points is flat at unity and changes nothing. Two points at the same level are a plateau. Two points at different levels are a ramp whose slope is the distance between them.
Points hold at the edges
The level before the first point is the first point’s level, and the level after the last point is the last point’s level. A single point at -6 dB is therefore a constant -6 dB across the whole file, not a fade into one.
That rule is what keeps a three point ride in the middle of a track from silently reshaping the parts you did not touch.
Decibels, not amplitude
The ramp between two points is a straight line on the decibel scale. Amplitude follows an exponential curve as a result, which is what a fader does and what a listener hears as an even move.
A line drawn straight in amplitude instead reaches most of its final loudness in the first third of its length. The difference is obvious on anything longer than about half a second.
The silence floor
A point at the bottom of the track is silence, not -60 dB of signal. The processor treats the floor as an off position so a curve drawn down to it mutes cleanly.
Everything above the floor is applied as written, including the smoothing that removes the step when a point is moved mid-playback. Moving a point while the file plays glides the level onto the new curve over about 10 ms rather than clicking onto it.
In a chain
The curve is one setting, stored as a string of seconds@decibels pairs, which is why it can sit in an audio workflow chain alongside compression and EQ. The points are absolute positions in the source, so a chain carrying a ride at 0:12 puts it at 0:12 on whatever file it runs against.
Up to 64 points are kept. Beyond that the extras are dropped rather than thinned, so a curve stays exactly what was drawn up to the limit.