Create your mother. It took me about a week, and I mixed four and water in which I had washed various fruit that had been in baskets in the kitchen. After a few days, it came alive and it has been ever since. I keep 2 jars of mother in the fridge, so that the one that is used one day has a whole day to recover in the fridge before being called on again.
My basic proportions have been this:
0. in the evening, take the jar of mother out of the fridge and feed it a soup-spoon of flour. Dribble some water in to get a thickl creamy consistency.
1. create the sponge with 100g flour (i have been using Shipton Mill Stron French) and 100ml tepid water, with about 25g of mother. I do this first thing in the morning and let it build and ferment for a couple of hours. I have ot found that timing is too important. I do this in a small cereal bowl.
2. at some point in the morning - again, precise timing not important - I get out a bigger glass bowl and mix 450g Strong White with 50g Wholemeal, 12 g salt (at this point, when dry, mix it all together), and add 375ml (g) of tepid water. I use dough scrapers or wooden spoons or a fork to mix it all into a sticky mass
3. Around lunchtime, I mix the sponge with the sticky water/flour mix in the bigger glass bowl. I use the dough scrapers to properly mix the two by repeatedly folding the sticky ball over the creamy sponge. You can tell visually when the 2 are pretty well mixed.
4. Occasionally during the rest of the afternoon, use the dough scrapers to do some more folding. I do this when I want a break from work, maybe 4 or 5 times.
5. Before going to bed, I put a bit of flower on the kitchen top, scrape the dough out of the bowl and onto the top, and do just a bit of stretch & fold. Not much. I also roll the dough on the kitchen top to make it into a nice smooth balloony whole.
6. I put the dough into a patterned bread basket (nice for visuals) and put it into the fridge for the night. At the same time, I get the second jar of mother out of the fridge for the next day's baking.
7. When I wake up the next monring, I put the oven onto 265 with circulation and place my big le-Creuset type pot into the oven so it also heats up. When the oven beeps that it has reached the right temperature, I put the dough into the Le Creuset-style pot, score it with a cross and sometimes dribble a tiny bit of olive oil. I close the lid on the pot, put it all into the hot oven, and set my phone timer for 25 mins. When the timer goes off, I immediately restart it, reduce the temp to 200, and take the lid off the pot.
8. Enjoy ans start again.
This has kept a family of 4 in bread for 3 months now.