There are a number of places from which you can obtain help with your Ubuntu desktop system, these include:
The Ubuntu Documentation Website - this contains this guide, and other guides produced by the Ubuntu Documentation Team for Ubuntu and Kubuntu.
The Ubuntu Wiki - this contains many guides contributed by the community.
Web Forums - here you can ask questions on a forum and receive answers from the forum community.
Mailing Lists - here you can ask questions by email, and receive answers from the mailing list community.
IRC chat: irc.ubuntu.com channel #xubuntu - chat in realtime with the irc community.
For more information, visit the How to Get Help wiki page.