All you have to do to install the IEEEtrans class is type:
sudo apt-get install texlive-publishers texlive-publishers-doc
But the best thing to do is:
- Download the IEEEtran.zip archive from here.
- Unzip it into some folder.
- Then create a folder latex in /usr/share/texmf-texlive
- Now, create a folder IEEE in /usr/share/texmf-texlive/latex
- Copy the content of the archive IEEEtran.zip into /usr/share/texmf-texlive/latex/IEEE
- run sudo texhash to let latex know that there are new files installed.
This way, you are installing all the files in IEEEtran and do not have to worry in the future.
For more info check the links in Useful Links for Latex.