How do you overlap layers in After Effects?

To overlap layers in After Effects, you primarily use the "Sequence Layers" feature with an overlap setting. Here's how:

1. Select the Layers: Select all the layers you want to overlap in the Timeline panel.
2. Access Sequence Layers: Go to Animation > Keyframe Assistant > Sequence Layers.
3. Enable Overlap: In the Sequence Layers dialog box, check the "Overlap" option.
4. Set the Duration (or Frames): Enter the desired amount of overlap. This can be in frames or duration (time). For example, entering '1' will overlap each layer by one frame. This means the next layer will start one frame before the previous layer ends.
5. Click OK: After setting your overlap amount, click "OK". After Effects will adjust the layer start times to create the specified overlap.

In summary: Use the Animation > Keyframe Assistant > Sequence Layers command and enable the "Overlap" option, specifying the desired overlap duration or number of frames.