public static abstract sealed class Editor.EditorUtility.Clipboard

Here's how to do some common things. Each has a code you can copy to your clipboard, then Ctrl+V to paste in the ActionGraph editor.

To motion edit, you select a time range of one or more tracks, then tweak the properties that those tracks represent to manipulate track data. You can also cut / copy / paste ranges of time, or save the selection as a separate .movie file.