Hi Morwen, still cooking projects...

When retelling a story, you must start with a "bottom line" - related to the original one, but not identical, and pointed at present-day audiences or readers. Sagas have many such bottom lines, so you can choose one. Then fit the rest of the story to your message - change it if it does not fit.

If you win the Nobel Prize in Literatur by this method, you will not be the first one.

A shorter folk tale might be easier for a start. The standard fairy stories have been "retold" in thousands of versions; reading and analyzing some of these may help you a lot.