First of all, yes, this is the right category.
Do you understand the concepts of time keyframes? If you do, you can use the V Key
to synchronize the cursor on the Keyframe Timeline with the cursor on the Replay Timeline.
If the Replay Speed Slider in the upper left corner is set to 1.0x Speed, the cursor on the Keyframe Timeline will be moved so that if you place a Time Keyframe, the speed between this and the previous Time Keyframe is exactly 1.0x.