This package requires the XGBoost shared library to be installed in your system.
The package is compatible with Weka >=3.9.1
It can be installed in Weka as an unofficial package (you can download a prebuild package from releases).
A GUI package manager is available from the "Tools" menu of the Weka GUIChooser.
You can install the package by selecting the zip file in the "Unofficial" box on the right.
The Xgboost classifier should then appear in the weka explorer under the "trees" submenu.