I need version 0.14 first and then 0.15?
You can't start a new game in 0.15. You have to play 0.14 first.
0.14 contains everything from start up to the end of chapter 9.
At the end of 0.14 you will be prompted to save. You load that special save - and only that save - in 0.15.
This is necessary to ensure that every decision you made while playing is taken over to 0.15.
0.15 is the beginning of chapter 10. Every following update will replace 0.15. The content of 0.14 is finished and locked.
The only reason for that is to lower the filesize. There is no carination in the story.
Until now there is only one elaborated route in the game: the "harem route".
Other routes will implemented later.
By the way, before you know it you will completely fall for that game...