The installation of the tbook RPM is not different from any other RPM installation: Download the file, login as root, and then input e.g.
rpm -i tbook-1.5.2-1tb.i386.rpm
However, tbook depends on other programs and it would have been very inconvenient if I had included those dependencies within the RPM system. Only one dependency is explicit: Saxon. But you get an RPM version of Saxon from tbook's homepage, too (http://sourceforge.net/projects/tbookdtd). Saxon must be installed before you install tbook. Saxon itself needs Java, at least version 1.1, although JDK 1.3 makes Saxon run much faster. Warning: You can't use tbook with Saxon 7!
On tbook's homepage you also get an RPM version of xindy.