To be fair, reading the product manual from cover to cover, over and over, is the best way to learn the entirety of the camera. I've only read the manual about twice, but I know little short cuts and tricks that the Pentax rep I spoke with didn't even know. I know it isn't ideal, but download the PDF of the manual and from there, upload it to your phone. Read a chapter here and there.
The second time you read it is when it really sinks in. Good luck!
EDIT: Here is the PDF ready to download if you wish.
https://www.pentaxforums.com/forums/115-pentax-k-5/249767-just-reference-k-5-...ml#post2666385