Type gunzip bnc2.4.8.tar.gz
Type tar -xvf bnc.2.4.8.tar
Wait for BNC to decompile itself to a directory.
Type cd bnc2.4.8
Type make
Now you wait while it configures itself.
Now you will need to download the example conf file from the download section and edit it, or edit the conf included with BNC. When your done upload it of course.
Type ./bnc bnc.conf
This will give you the bnc information. Open mIRC or your IRC client and type /server <your vhost> <port>. After that, follow the steps it tells you and your bnc will be ready.

If you have any problems contact your shell's support team.