If you have kernel version 2.2.15 or higher, it probably won't work it was designed for 2.2.14. You can go to a couple winmodem sites and they have info on a hacked version to work on 2.2.15 and greater.
If you have the right kernel, it's pretty straight forward. It loads a kernel module to make the modem work with Linux.
The following files are found inside the driver download file.
|ltinst||654 bytes||6 Jan 2000|
|readme.txt||881 bytes||17 Aug 2000|
|ltuninst||616 bytes||6 Jan 2000|
|ltmodem.o||552.9 KB||6 Nov 1999|