In a bowl on your food scale, add the dough ingredients to your mixing bowl. Mix together until well combined. The dough will be loose and sticky, but resist the urge to add more flour.
Allow the dough to rest for about 30 minutes, then perform one set of stretch and folds. I usually do 8-10 stretches during this set to get ahead. Leave the dough to rest again for another 30 minutes.
Mix together your seeds into a small bowl. This will help to evenly disperse them when added.
During your second set of stretch and folds, add in the seeds and oats about a third at a time. Continue the stretch and folds until the seeds are well dispersed and the dough is strong and smooth.
Cover the dough and allow to bulk ferment 8-10 hours.
After the bulk ferment, dump your dough from the bowl, lightly shape into loaf, and add to a loaf pan. From here, you can allow it to rise for just an hour before baking, or you can place in the fridge for a cold proof to develop the flavor a bit more. If you chose a cold proof, allow the dough to rise a bit before placing it in the fridge.
When you're ready to bake, preheat your oven to 400℉, score your loaf once down the middle, and bake for 10 minutes. Remove the loaf from the oven, and turning your lame at an angle, expand the original score. Place back in the oven for another 30 minutes.
Once the loaf is finished baking, cover with a towel on the counter to cool. The towel will allow it to steam and soften the crust for that familiar sandwich bread texture. Allow the loaf to cool completely before slicing and enjoying a delicious sandwich.