You have often pretty nice recipes - without the pumpkin :) - but this one is rather cringeworthy. And not german at all.

Firstly: do not try to make Sauerkraut at home. It is not easy to get it made really well, you need experience, special pots and a lot of time for that.
Canned (or otherwise packaged) ready made Sauerkraut is cheap and you wont get a better one if you make yourself. Most likely the opposite.

Second: do not pour the juice away that is in the can! Do not wash the Sauerkraut! Its fine as it is.
Third: no tomatos or tomato or tomato paste. Njet.

What you do need is some potatos. Not too many, about the quarter to a third of the weight of the Sauerkraut. Peel and cut in small dices. Some carrots are ok, but purely optional. Just a few, not many.
As for spices, you need 1 medium sized onion, bay leaf (just 1 or 2 leafs) and clove (4-5 pins). Pepper is better used as ground, not whole. Its hard to fish them out again when ready.

Appllication:
Cut the onion in half. Take the big pot you want to make the stew in, and put in a bit of neutral oil (sunflower or so), just so the pot is oily on the bottom.
Take the 2 half onion pieces, and nail the bay leaf on the round side by using the clove pins. Now put the onions with the flat side down into the pot, and heat it up. Fry the onions until the flat side is nice brown.
If they are, put a bit of water into the pot. Just a little bit, to make them stop frying so they dont burn.
Now put the Sauerkraut and the diced potatos in. Put the onion s in a top layer, so you know where they are and you dont destroy them when you stir the stew. Do not put the carrots in yet, its too early for that.

Now to the meat. I guess best is a smoked pork back (Kassler in German). Cut into dices or use as whole piece - then you can cut slices from it when you serve the meal. Another option are smoked pork sausages (Mett-enden), like 1 or 2 per person. Do NOT use chicken! Double Njet! :)
Put the meat in at the beginning as well.

Well, now let all this cook in the pot, at least for 35 to 45 minutes. The potatoes have to be really soft. Now add the carrots and boil another 10 minutes. At the endtaste it and add salt if needed. Sugar only very little, if any at all. A bit of Maggi soup spice is nice as well, if you can get that in your shops. Finally, remove the onions with the bay leaf and clove before serving the stew.

That is a german Sauerkrauteintopf. As a vegetable side dish, its basically very similar, only without the potatos and carrots. And with a bit of smoked ham instead of Kassler or Mett-Enden, since its served with pig foot and mashed potatos (the famous Eisbein + Sauerkraut) or similar stuff. And always pig meat, everything else is sacrilege. There is a recipe from the north sea coast, that has Hering in it - that is awful I think.It is called Labskaus, if you want to look it up.
Well, so much for todays Sauerkraut crash course. :)