Timeline: Cannot move file to front of exiting files or somehere in between

Newby here. How to add a video file at the beginning or somewhere in the between existing frames on the timeline. I was expecting when I move the file in the front or between existing frames, the frames after will be moved to the right, making place to the new file. I am wondering why this is not possible. Instead I am only able to add the file at the end.

Put the clip in the Source viewer and press the Paste button on the Timeline toolbar. Or, if using drag-n-drop from Playlist, for example, first turn on the Ripple button on the Timeline toolbar. At this time, you cannot move a clip to somewhere that is not already a blank area. But, you can use standard cut and paste: select the clip, cut it (Edit > Cut), move playhead to new location (double-click a clip to seek to its starting point), and paste it.