The package can be downloaded from https://gap-packages.github.io/sglppow/
Then tar -zxvf slgppow.tar
produces a directory sglppow
. This should be
moved into the pkg directory of a GAP installation.
The package is set up so that after loading it into GAP with LoadPackage("sglppow")
the full functionality of the package is available.
sglppow manual