ahoyyyy over thereeee!
Good place to start is to learn about the 'golden triad' of exposure..
Exposure 101 - The Golden Triad - Learn Photography. Fast. is one resource. Perhaps the best thing to do is read a little and then attempt what you think you know... trial and error! But, in this case, some well crafted trials (as well as well crafted errors perhaps!) hehe
Also, you may want to set your K-r to shoot in DNG format (RAW) as you can adjust exposure, colors, etc much more largely than if editing a JPG format image. And then the fun is in getting some photo editing software..
RawTherapee Blog RAWTherapee is one.. but there are a bunch of them (some free such as RT) just to get started!
Or, RAW+ if you want DNG *and* JPG format photos taken at the same time (eats SD Card space though but maybe not a bad thing if you are practicing)
Please avoid staying for long periods of time in the rumors+news forums -- lots of grown men acting like even older men in there.