well, the fact that it's pirated is not really related to the quality of the game so I don't really get this this comment *smiling sweat drop emoji*
Said that, calling the game bullshit just because you aren't able to unlock some CGs is mostly just childish. Ergi is a (very elaborate) variation of a puzzle game, so of course it doesn't give you 'instructions or explanations' on a silver platter -that's the heart of the game!
However, I appreciate the frustration because some paths are not easy. First of all, in Ch3 you have extended scenes just for Tyr, Borge, Ralf and Kirk. You have additional (naked) scenes with the other five but not an extended final sequence. Also, the aforementioned extended scenes are not that extensive as the ones in Ch2 (meaning, no fun minigame). There is sex but don't expect extra-steamy acrobatics.
In any case, in order to unlock the final scenes first of all you need to select the 'flame' option for the chosen love interest (and you can choose only one flame option among the nine, once you choose it the other flame options don't appear even if you have the prerequisites) Side note: if you want to unlock the final CG of the five people that don't have an extended scene you also need to select their flame option.
Then you need to have high specs with that specific person, I don't remember how much exactly (I think it's at least 40 of the stat favoured by that person: attraction for Kirk, affection for Borge, admiration for Ralf and Tyr) but if you aim at wooing that specific person I assume you tried the options that raise his stats (Ralf and Kirk might need high masculine level as that's what they're attracted to).
Finally, it's mostly a matter of making the right choices during the scene when you visit home almost at the end of the chapter (2 days before the countdown ends). Basically every good choice (starting from the moment where you decide how to overcome the crowd of wolves at the door) gives you one or two points, and if you have more than X point at the end of the sequence, the nice scene unlocks. So you can save just before that scene and try the options (and let the answers and reactions of the person guide you a bit if it's a good or a bad choice) until you get the right choices. Maybe a bit tedious but you don't have to repeat the whole chapter from the start, just that bit!