How to execute .i386 files?

[skemmdarvagr]

I didn't really know where to post this, but I'm a newbie, so I guess it fits here.
I've used Debian 9 for a bit, but I'm basically a Linux functional analphabet. I've downloaded this game, Urban Terror, which in theory should work fine, but the .i386 doesn't want to open. Is it just me or do I have to do something to make it work?

(I didn't try to open it in console, since I don't even know how to do it and the help command didn't really do much other than confusing me)