Finally got the hang of it.

450g flour
300 water
100g active sourdough starter
10g salt

4 to 5 stretch and folds every half hour
Then bulk rise until double in size (I stopped looking at the clock, apparently my starter is very active and it over ferments)
Then in the fridge over night or about 12 to 14 hours.

Preheat my Dutch oven for 45 minutes at 220 centigrade
Bake for 20 minutes with 4 ice cube
Another 20 minutes without the lead.

Very happy with the results.

Thanks to everyone who helped along the way.