Ritualisto: As flclafi said before you can start the installation by double clicking part 1 (it is the exe-file; the rest are bin files). After that you can install patch 1.08 the same way. Just double click the exe-file.
If you want you can import the game to GOG Galaxy (but there is no need, only if you are interested in achievements). I wouldn't recommend to use Galaxy now but it is up to you. You can test it and if you have problems start the game without Galaxy again.
Here is a guide how you can import a game to Galaxy (for you it is number 1):
== IMPORT ALREADY INSTALLED GAMES TO GALAXY ==
1. For GOG games installed using installers from the last few months (so called Galaxy-compatible installers)
Click the "+" button on top of the sidebar and select "scan and import folders" - it will find all compatible games within that folder and add them to the Client.
2. For remaining GOG game INSTALLATIONS
Find the game in the Library (click on the image of the game), then click the More button and select "Manage" -> "Import folder" and point the folder selector into the folder where that game is installed.
Please be aware that Client will accept any folder pointed to and will overwrite files inside it (this can for example wipe some mods or damage other apps in case of pointing to a wrong folder) and will update the game to the newest version (current default language English).
Source:
http://www.gog.com/forum/general/gog_galaxy_beta_2/post1 Thanks guys, I though game needs galaxy to run and update such steam and origin games, so if not, I'm going to remove galaxy now as I had a real bad experience using that!
