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. It is now the scope of the Inspector, quickstamp, stamps, and all other controls. Normal shortcuts, such a spacebar, will open the text window.
Dragging a note horizontally within the main view will update the $StartDate (and $EndDate if one) according to the moved-to position.
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.