From tarball: your kernel must have USB support compiled in or as a module. You'll also need the sources of the running kernel, and these sources must be configured. Uncompress the archive, cd to the "tiusb" directory and run "make" then "make install". This will build and install the module.
As built-in: uncompress your kernel, type 'make xconfig', go into the USB char devices section and set TIGL as built-in or module.
You may need to create devices entries: do an 'mknod c 110 15 /dev/tiusb0'.
Think to set perms with: 'chmod 0660 /dev/tiusb0'.
To load the module, either use insmod or modprobe the usual way, or run "make load". To unload the module, use rmmod the usual way, or run "make unload".