For more info on the KXStudio applications such as Cadence, Claudia and Catia
To check to see if your sound device is supported by GNU/Linux, check the ALSA SoundCard Matrix
http://www.alsa-project.org/main/index.php/Matrix:Main
If you have a FireWire audio device you will want to check the status of your device in the FFADO Device support database
http://www.ffado.org/?q=devicesupport/list
Another good resource for GNU/Linux audio hardware compatibility is the linuxaudio.org Current Audio Gear page
http://wiki.linuxaudio.org/wiki/current_audio_gear
To check for the compatibility of your printer with the GNU/Linux printing system, CUPS, check the OpenPrinting database
The Ubuntu package archive search
The linuxaudio.org wiki has a comprehensive list of all GNU/Linux audio and sound software
http://wiki.linuxaudio.org/apps/start
Libre Graphics World provides news and other resources relating to free graphics software
http://libregraphicsworld.org/
Freecode maintains the Web's largest index of GNU/Linux software
The Wine Application Database (AppDB) details the compatibility of Windows programs with Wine
To get the most out of Linux, you need to understand how to use the terminal (aka console). Here's the Ubuntu beginners guide to using the terminal
https://help.ubuntu.com/community/UsingTheTerminal
KXStudio uses the KDE Desktop Environment by default. Here is an introduction to the KDE 4 Plasma desktop
http://userbase.kde.org/Plasma
JACK was created mainly for Ardour which remains the most popular open source DAW. Sadly its not the most intuitive app ever so you may want to read its manual
Those who prefer the more lightweight DAW qtractor will be happy to hear it has one of the best free manuals available for a free and open GNU/Linux app
http://downloads.sourceforge.net/qtractor/qtractor-0.5.x-user-manual.pdf
Remember that KXStudio the distribution is based upon Ubuntu 12.04 aka Precise so any instructions or software you find for Ubuntu (precise) will be compatible with KXStudio.
If you get stuck, the first place to search for a solution is on the KXStudio forum
http://linuxmusicians.com/viewforum.php?f=47
If you suspect its more of a general Ubuntu issue it would be a good idea to search for help on the Ubuntu fora too
The LinuxAudio wiki contains all sorts of useful info for Linux audio users, including this manual
If you can't find an answer to your question on the fora or with your favourite search engine, IRC is going to be your best hope of getting help quickly.
KXStudio includes the Konversation KDE IRC client which you can use to connect to the following channels on irc.freenode.net
#kxstudio is the official IRC support channel for KXStudio
#opensourcemusicians is the IRC channel of the open source musicians podcast
#ardour has its own official IRC support channel on freenode.net as do many other popular open source projects
#kde is good for general issues with using the K Desktop
#ubuntu is the support channel for general Ubuntu system issues