Issues with running Kotlin files

I'm fairy new to IntelliJ, so first of all, sorry for the noob question 

So as I'm learning Kotlin, i'm creating one independent kotlin files after another, learning and writing codes. Until recently, every file worked individually, that is when I pressed "Run" on a file, just that file would run, but now, as I'm writing a new file, and I right-click in order to debug or run, those options are gone, though I can see a "Run" button in the "Top" menu, though when pressed, the previous file starts running... 

I'm pretty sure I'm at fault here, but I don't know what it is I'm doing wrong. 

Any suggestions is much appreciated :)