Hello Rahul,
This Lidar Building Footprint Extraction Tool is not supported by Esri or is it created by Esri. I would suggest contacting the Earth Data Analysis Center. They developed it for extracting building footprints in New Mexico and are currently testing a new prototype tool that should be released in the Local Government 3D Basemaps | ArcGIS Solutions for Local Government provided to them. I compared the results of the Lidar-Building-Footprint-Extraction-Tool developed by Earth Data Analysis Center and it's results were not as good as the tool being added to 3D Basemaps or the process below, a basic version of the processes in the Esri supported tool to be released.
Here's suggestion of a process to get you started on building footprints.
1.Use Classify LAS Building
2. LAS Point Statistics As Raster with a filter on the las for only buildings and output to 2x pixel size of your LAS spacing.
3. Elevation Void Fill raster function with to fill gaps in the raster, say a 0.5 for Short Range IDW Radius and a 20 for Max Void Width.
4. Raster to Polygon using the Elevation void fill raster.
5. Run Regularized Building Footprint on the features using the Right Angle and Diagonal option.
Thanks,
Arthur Crawford - Esri