Reviving a Dehydrated Starter, Step by Step

Day 1: crumble the flakes into 20g warm water. Wait 20 minutes, then stir in 20g bread flour. Cover loosely.

Day 2: you should see small bubbles. Discard half, feed 30g water + 30g flour. Repeat 12 hours later.

Day 3: it should double within 6 hours. Once it does, it's ready to bake with. Store it in the fridge and feed weekly.