if you don't use the RPM distro, u can simply download the gzipped tarball (i assume yours is opera*****.tar.gz or opera*****.tgz or soemthing like that. it's a harder way to configure but hey, that's the dirty work that we enjoy
start a terminal session, go to the folder contained the file and type
(replace the filename.tar.gz with the real file name
now you should have a file called filename.tar
tar -xvf filename.tar
now you sholud see it verboses a load of filenames and folders.
go and check the folder it created, and go into it
there should be an install script or install-bin. run it by typing:
replace ./install with any of the script that they have
you should be done then,
the installation should prompt you for a folder to install opera - remember that - and run the "opera" executable in there to run opera.