How to change themes in UBuntu?

I would like to change my theme on Ubuntu but I dont know how. I looked through the internet and i did all the steps but when i get to install it on my computer it says it's not a valued theme. it says it has to be .gz. I dont know how to change it to that. PLease tell me how... thanks:)How to change themes in UBuntu?
On Karmic (9.10), you can click (on the top panel) System %26gt;%26gt; Preferences %26gt;%26gt; Appearance. Alternatively, you can right click on the desktop and click on 'Desktop Background'. Then click the 'Themes' tab. If those on your system aren't good enough for you, you can click the 'get more themes online' link.



For much more extended eye-candy, open the Software Center and install Compiz with the settings manager, etc. Enjoy the famous rotating cube desktop!



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Sorry, misunderstood a bit :(

When you downloaded the theme from wherever (likely the Ubuntu website) it was a gzipped tarball (theme.tar.gz), a compressed directory (much like .zip) You probably extracted it yourself (it would automatically open under the archive manager), but (apparently) Ubuntu theme installer thingy won't have it. When you click 'Install' from the theme dialogue, select the original .tar.gz file. It is probably in the Downloads folder.How to change themes in UBuntu?
UbuntuEyeCandy

https://help.ubuntu.com/community/Ubuntu





LUg.