You have to download all 7 files (one exe-file and 6 bin-files) from your library. Go to Account - Library - Witcher 3 and download all 7 files (on the left side of the pop-up). Like you did with your bin-file.
After that double click the exe to install. Or use Galaxy and install the game with that. It will download all you need by itself (but keep in mind you don't get the install files for a later install this way). You need to click the more button and click on backup (I don't remember the exact wording). Now Galaxy will download all you need for a later manual install.