I am absolutely new and I don't know many things, so please be patient with me.
I have installed the KDE O/S and desktop into a HP Chromebook 14 today in the morning. Then I turn off the computer and when trying to get access to KDE in the developer mode even I have pressed Crtl+Alt+Shift+> the KDE O/S does not activate. I am lost and I need specific instruction in how to make it work. I have search all around the internet and there is not a word of anything similar.

Thanks.

you did not install the "KDE O/S" you installed a Linux distribution that has KDE as its desktop environment, possibly a variant of Ubuntu like Kubuntu, if so I would suggest checking out their forums http://askubuntu.com/questions/tagged/chromebook or the forum(s) of whatever you installed. FYI you 1st need to get Linux to start before KDE can be started.

I don't recall seeing such a topic on this site so you may not be best served here but you will need to provide more information no matter where you post including:
- what distribution of Linux did you install and what version
- how did you perform the install and were there any errors displayed during the install
- what if anything happens when you ctrl+alt+shift

ps - "forum feedback" is specifically for feedback regarding the forum I have moved this to Operating System Specific -> Linux