Opening a file from the keyboard

[Foggy]

Ok, this is going to probably sound like a really stupid question but when a file is highlighted and I hit 'Return' it goes to rename the file - so what do I hit to open/run that file? (Without using the mouse...)

 

[ChrisBrightwell]

cmd+down

 

[GimmeSlack12]

or

cmd+O (for open)