Change Default to T/Bird & Firefox

[Clark]

I have just loaded Kbuntu.
Question:
I want to change my default Email to Thunderbird (and Firefox browser) 
but the method given in Q/A 7077 (see below for link) is to " Navigate 
to System \ Preferences \ Preferred Applications"  I can find System in 
the K Menu but there is only an array of programs; Adept, Dolphin etc.  
I can't find any trace of Preferences can someone help.

Clark

https://answers.launchpad.net/ubuntu/+source/kdebase/+question/7077