The guide is up on Steam as well, but it is age-gated and Steam is very very bad at communicating this. You'll need to go to your account profile, then adjust your store preferences to allow Community content for games that contain "Frequent Nudity or Sexual Content". We think the fact Obscura has this tag is extremely silly and wouldn't have applied it ourselves, but since Valve decided we need it all Community content (including the guides) are completely hidden from you until you change your store preferences.