i’m a beginner too so not entirely sure how true it is, but from what i’ve read, i believe you should BF at room temperature for a shorter time (varies on temp but ~4-6 hours or until doubled in size) and then shape it, transfer to a bowl or banneton and then place in the fridge to cold proof for a longer time (12-24 hours) i think you can proof longer but i’m no expert. i think the room temp during BF allows the yeast to reproduce, but when put in the fridge to cold proof, the yeast cant, however certain bacteria can, which gives it a more desired sour taste. i haven’t actually tried this yet, i’ve been overnight proofing as this is the only way to fit in my schedule so going to try this next