Cook the carrots and the potatoes in boiling water until soft (about 20 minutes), then grate using a small grater.
Cook the beets in boiling water as well, until soft (about 1.5 hours), then grate using a small grater. If too liquid is produced you can pat dry using a paper towel if you don't want a soggy salad.
Finely chop the onion, and pour hot water on it, then get rid off the water. Again pour cold water on it, and get rid off it. This will help you get rid of the bitter taste. Pour white vinegar on it and keep it for 5 minutes, then again wash with hot water and then get rid off it.
Take a huge plate preferably round, and start layering the salad. Layer half of the beets on the plate, then layer half of the shredded potatoes, and then layer a thin layer of mayonnaise.
Layer all of the onions, and again layer with a thin layer of mayonnaise.
Cut the herring fillets in pieces, and layer all of it.
Layer with the other half of the potatoes followed by thin a layer of mayonnaise.
Layer all of the carrots, followed by a thin layer of mayonnaise. And then the rest of the beets followed by more mayonnaise. Make a pattern with the mayonnaise using a fork.
Decorate with greens, I decorated with chopped scallions.
Refrigerate overnight, and serve on the next day.