To fully understand the K system you have to do a few things first:

Know that there are two aspects of a signal peak and rms.  (By peak I am not referring to the top part of a continuous sine wave as in electrical engineering. I am talking about how high the signal gets during the attack or leading edge transient part of the signal. eg an acoustic guitar string plucked with a pick. The sound will jump up quite high to a peak value first then after all that will  settle down to an average or rms value)

There are meters that show either. Peak meters (on most DAW's) and rms meters.
VU meters are good for RMS. There are other good rms meters too. (note rms meters are slow in responding. 300 ms in fact to reach 0 dB so they don't show peaks or respond to them they tend to only show the rms component)

A digital reference level is chosen to represent 0dB VU rms. eg K-14. When an rms signal is created down at -14dB your main rms or VU meter will show 0dB VU. There is 14 dB of headroom above that.

You need to CALIBRATE your system. You need to import K system levels (sinewaves) and play them back and get the rms meters to show 0 dB at these various levels. You need to be able to quickly change your ref level calibration to suit different types of work you may be doing. Without calibrating your system first you are nowhere!

You need to read two very important articles from the Bob Katz website.

http://www.digido.com/articles-and-demos12/13-bob-katz/22-level-practices-part-1.html

http://www.digido.com/how-to-make-better-recordings-part-2.html 

Once you understand and done all this you can then import and compare commercial recordings. Many commercial mastered CD's end up with a much higher average rms than K-14 or K-12. Many get up to K-7 or K-6. These are not official K ref levels as such but I have created them in order to measure how loud commercial CD's are.

You then change the calibration to suit mastering levels and do your mastering to match. (If that is what you want that is)