Before being able to export .EAD files from 3Ds Max, you'll need to install the exporter:
Check the folders in the package you received from the ARLab's 3D Engine. Into the Exporters/3ds_max folder you will find a file called EAD Exporter.dle. Select it and copy it.
You need to paste the file (EAD Exporter.dle), inside the stdplugs folder into the installation directory of 3ds Max.
Start 3ds Max (restart it in case it was already started) and you'll now be able to export in .EAD format from the Export menu. Want to make a test? Check this documentation to create and export a basic scene!