Mix everything together and pop it in the fridge overnight.
Or if you want to use some or all of it straight away, give it all a good knead for about 10 minutes, or if you have a food mixer, use the dough hook for 10 minutes, or you can use a food processor, process for 5 minutes. Cover the bowl and leave it in a warm place to prove for an hour or two, until doubled in size. Flavour develops in this time, so leave it as long as you can.
I leave the dough in the fridge, and every two or three days, I feed the yeast, adding a mug of flour and a splash of water. Take out want you want to use. Any dough left at the end, or flour on the worktop, ie you made too much for the flatbreads you wanted, mix it back into the bowl of dough. Keep the mixture loose, it’s better for the yeast, so you may need to add a little water as well.