@MisterLemon I agree, I'm actually trying to translate this myself and I kinda just ignored all sense of logic and translated it like a poorly explained isekai. If I take too long though, someone can PM me for what I've come up with so far. (Finished translating with my poor jp and help from Google translate but waiting on a friend to edit the images)
Edit: I take back what I said, the reason this doujin is so random is because it's a trial run for the full version. So the events are probably really rushed and not explained because the artist had no time to draw.