Do NOT preheat the oven. The bread is placed into the cold oven.
Combine the yeast with the warm water and stir. Then set aside until you have mixed up the dry ingredients.
Line a loaf tin with baking paper and sprinkle some oats into the bottom.
Then combine the rest of the ingredients (flours, salt, vinegar and seeds) in a mixing bowl. If you are mixing by hand, I prefer a wide and shallow bowl. If you use a hand-mixer, a tall bowl is easier to use and make sure the dough stays in the bowl. I have also successfully used a stand-mixer for this recipe, but it is not required.
Add the water-yeast mixture into the flour mixture and stir until well combined. The dough will be rather sticky and wet. Carefully transfer the mixture into your prepared loaf tin.
Sprinkle the rest of the oats on top of the loaf and immediately put it in the oven. Then set the oven to 425℉. After 55 minutes, take the bread out of the oven.
Let it cool for a few minutes, then remove the loaf from the tin and set it on a rack to cool completely.