Control + K in Windows. Command + k on a Mac should open Preferences.
You'll need to use your Operating System to associate image file types with Photoshop CC.
Just make sure that's what you want. It'd drive me crazy if Photoshop opened every time I clicked on a JPG.
There are two levels: The OS (Mac Finder or Windows Explorer) and Bridge.
In the case of jpegs on my Mac, I open them in Preview at the OS level.
If I want them to open in Photoshop, I open Bridge CC, and then double-click on the thumbnails there, which opens them in Photoshop.
Photoshop is usually the default editor for Bridge.