When you insert a clip into the timeline, you can choose to insert it at the beginning, the end, or the seek slider's current position. All tracks in the timeline are moved by an amount equal to the duration of the inserted clip. This may create a blank space. To insert a clip without affecting other tracks in the timeline, Lock those tracks before inserting.
To append the clip to the timeline, use "Add to Timeline" instead of "Insert into Timeline" from the Edit menu. To move many clips at the same time, select all tracks you want to move by holding down the Ctrl key, then use the arrow keys on your keyboard to move them. To nudge the clips, hold the Shift key while using the arrow keys.
