There's a tutorial here:
Pentax Digital Camera Utility - A Mini Guide - PentaxForums.com
I haven't checked to see if it is up to date, but it should give you some clues.
PDCU takes a bit of getting used to, and it isn't the best tool for processing huge numbers of RAW files, but it does produce great results that are very similar to the JPG images produced by the camera. Personally, I will use PDCU for one-off image processing. If I have a bunch of similar images to process (eg. from a trip), I'll use something like DxO. Everybody has their own preferences.
Part of the problem with providing help is that I set PDCU up on this computer years ago, and I can't remember what you see when you first install it. I know one thing that is confusing is that PDCU has two modes - browser and "laboratory". By default, it comes up in browser mode, and you have to click on laboratory near the top left of the window to bring up all the editing tools. I arranged all the tools to suit my tastes, so I don't know where the cropping tool, etc. will appear on your screen.
My theory is that PDCU is essentially the same software that is inside your camera, with a rudimentary UI added on. This is the only explanation for the fact that it includes all the same settings that the camera has, and can generate output that is virtually identical.