Prerequisites
This addon depends on PyMeshLab. The easiest way to install it is using pip
Install pip
Open the terminal or PowerShell. Go to the directory where Blender is installed.
Move to the directory 'python/bin/':
cd python/bin
Install pip:
./python -m ensurepip
Install dependencies
Install PyMeshLab:
./python -m pip install pymeshlab
Install Python-xNormal:
./python -m pip install xNormal