From your maintenance starter take 25g and place it into a clean jar. Add the flour and water and mix with a spoon. This is now a leaven and can be used to bake with.
When the leaven has fully risen, take half to use to make a loaf of bread. The remaining half to dehydrate.
Smear the starter on parchment paper on a baking tray. Now leave at room temperature or even in a linen cupboard for 2-3 days, to completely dry out.
When it has dried out, peel away the parchment and break it up into small shards. Store in a jam jar.