Ensure you meet the minimum requirements.
Download the entire library.
Uncompress and extract the archive into your installation directory.
% cd [install_dir] % gunzip -c acs_idl.tar.gz | tar -xvf -
Edit acs/bin/start_acs to customize for your site.
Optionally add the bin subdirectory to your path.
The software may now be started by the bin/start_acs script.