If you don't have the game installed, you will want to download this package Game Client (1040 MB)
If you already have the game installed you can just download the launcher and place it within your Prince of Qin installation directory. It will download the necessary updates to play.
You can either install webkit2gtk-4.0 for the UI mode of the launcher, or you can launch it with "--cli" and get a cli mode.
You'll need to be sure Wine is installed otherwise the game will not start.