After reading the help file README.TXT you can grab the appropriate files via annonymous FTP.
Please let us know if you do so we can keep you informed about the upgrades and bugfixes that come out every few days. Just send email to: firstname.lastname@example.org asking to be added to the CARTHTML mailing list.
The first time you download you will need to take the whole kit which, in addition to the latest executable contains some shareware executables that you will need to prepare the demonstration files and to get started on your own data sets.
Subsiquently you will only need the updated executable and/or the demodata set.