Boil and cool the potatoes and eggs the evening before, or the soup ends up lukewarm and there is no point to it. Salt the diced cucumber first and drain it — otherwise it waters the kefir down within ten minutes.
It did not make it into the plan for these seven days.
The method above is what decides the dish, not a step-by-step recipe. The link runs a web search on the name: this page has no vetted sources of its own, and will not invent any.