Timeline view is not a 'view-only' format. Items shown in the main panel or either of the sidebars (no date, out of range) can be editing and items either added or deleted.
To edit a note (or notes) simply select the item(s). This becomes the scope of the Inspector, quickstamp, stamps, and all other controls and populates the text pane.
Dragging the event's title wider than the default width will alter the duration by updating $EndDate. If no $EndDate was set previously, an appropriate $EndDate will get added and set.
Dragging an event vertically, will move it to a new timeline band (if present) or dragging to the bottom of the current view will create a new band. Note that bands use alternate colour backgrounds to make them easier to tell apart.
Dragging an event vertically within a band is not possible. To alter the listing order, open an outline view.
Shift-dragging vertically will ensure the $StartDate does not change, e.g. whilst moving a note into a new band.
Deleting a selected note in the timeline, deletes as normal, i.e. from the TBX and not just the current view.
See dragging undated and out-of-scope items to/from the timeline.