XlsxLibrary is a library for reading (and soon, writing) spreadsheets saved as .xlsx files. If you need to read .xls files, you might be looking for XlsLibrary.
XlsLibrary is a Robot Framework wrapper for the OpenPyXL package.
Usage guidelines can be found in the Keyword Documentation.
Since this is not a complete python package yet, there is no installation needed. Although the openpyxl package is a pre-requisite:
pip install openpyxl
Just import XlsxLibrary as a normal user library in your project. More information on importing user libraries in the Robot Framework User Guide.
*** Settings *** Library XlsxLibrary.py