Lattice Algebra Toolbox documentation can be found in different places:
readme.txt: the downloadable sources contains a readme file with information about the sources version, changes and usage.
Help and demos: all the functions are provided together to help files and demonstration code. The help can be accesed through the help tool from Scilab. The demos are located in the 'demos' folder.
LAT manual: it is also possible to download the (at the moment, on work) LAT manual. The manual constains information about installation and usage, as well as basic Lattice theory and examples.