How to narrate a complete story into a single painting?
There are multiple ways to narrate a story in one painting. Some were already pointed out in the comments to your question.


The comic book way: By this I mean the arrangement of the scenes in multiple frames that are all on one painting (a comic that consists of only one page if you will). There are multiple ways to arrange the frames but most commonly the reading order of the intended audience is used. In the western world you narrate from left to right and top to bottom, whereas for manga its right to left and top to bottom. Text may be used to develop the scene, but the distinguishing feature are the multiple frames. Example: Wendy


If by 'in one single element' you mean that you don't want to use multiple frames there are still some options:


Composition: In painting the composition is the most important factor when it comes to telling a story in one picture. Setting up your narration you have to think about where the story begins: this will correspond to a section in the picture the eye of the viewer is immediately drawn to. This can be achieved using size, light, color, or the place in the image (usually a viewer 'reads' the image from the top left to the bottom right). Using a decreasing amount of emphasis for the following scenes, the eyes of the viewer will gaze along the line of your story (look for books about composition and see also this article mentioned by John Vukelic in the comments).
Format: if you use an unusual format for your painting the composition to tell a story might be easier obtained. Taking a really wide format - like for a panorama - the viewer will not be able to capture the entire image with all details in a single glance and thus has to digest the image sequentially, which is ideal. Psychology suggests that most humans will start from the right (e.g. Werner Tübke's 'Peasants War Panorama').
Another example would be to have a picture whose height is large compared to the width. The movement of the eye will then probably start at eye-height of the viewer and then move up before it goes down again.
Put a lot into the image. Some pictures of the early (middle European) renaissance will simply contain a lot of scenes connected by landscape or other (most notably the images of Hieronymus Bosch and Pieter Bruegel. With this approach it will be harder to tell a strict-time-line-story without using further tricks, as there is simply too much going on.


Basically everything boils down to the composition of your painting when you want to narrate a chronological story. Planning carefully and sketching the composition is mandatory to get a satisfactory result.

See also this blog-post about narrative.