when i installed ubuntu studio i just selected 1024x768 resolution and 2 lower ones (my mistake) but now i just dont know how to add a new resolution, im very new in linux so any help will be apreciated, thanks.

You will need to manually edit your /etc/X11/xorg.conf file to add the higher resolution choices. If you are unfamiliar with manually editing configuration files, then it would be best left alone. Incorrect editing could cause you to lose your graphic interface entirely.

Another semi-graphical method would be to run this command in the terminal as Root... or in your case Sudo:

This command will bring up a semi-graphical configuration wizard. Just follow the steps.

Lastly, some resolutions are not attainable unless high performance video hardware drivers are installed on your system. 1024X768 may be the highest resolution you can achieve with the generic video drivers provided by the operating system.

Luck!

are you using an nvidia card? If so, do you have nvidia-settings installed? If so, it's pretty easy, just run nvidia-settings as root, or via sudo (i.e. "sudo nvidia-settings") go the the "X Server Display Configuration" and change the resolution to how you'd like it. Once you're happy, click "Save to X-Configuration File" and you're done.

If you don't have nvidia settings, you have to do it the hard way (at least, that's the only way I know how), which is to edit your xorg.conf file. If this is the case:

sudo nano -w /etc/X11/xorg.conf

then look for a line that sayd "Modes ...."
on that line you will see your possible screen resolutions, the first one it sees is the one that is used, so add a new one at the beginning. Make sure to form it like the others, i.e. "1600x1200" - with quotes and no spaces. Leave spaces between entries, i.e. "1600x1200" "1024x768". Quit, save, & you're set.

When you're done, log out, then hit cntl-backspace (or just reboot) & you should be up with your new resolution. If it doesn't work, you'll get an error message, be dropped to an old-timey shell where you can edit out your last changes. in old-timey shell, the command "reboot" will restart your computer.

Good luck!

sudo dpkg-reconfigure xserver-xorg