Registration of tourists in Belarus

In this post I will explain most of what you need to know about registration when you travel to Belarus as a tourist on a visa valid for no longer than ninety days. The information comes from my personal experience, acquired along the several trips I've taken to that country. Along these lines I will mention Russia several times, since both states are direct inheritors of the same system and their rules are pretty much the same, varying mainly in the deadlines and ways to register, but the particular details I will provide down below apply only to Belarus.