I use Linux which files do i use
You can't run Traktor on Linux or ChromeOS.
For linux you can use Mixxx. It supports a lot of controllers.
Traktor might work with wine, but I don't know.
So you have a Chromebook using ChromeOS. Which isn't Linux. Neither runs applications for Windows or Mac OS.
So how do i downlioad files
What files?
There is no traktor for chromeOS.
AFAIK, Chromebooks neither have an X86 CPU, nor it is easily possible to replace the ChromeOS with anything else. Therefore, possibly neither Mixxx nor Traktor can be installed anyhow.