Louvain-la-Neuve has its own train station (location D6 on the detailed map). There are three main train stations in Brussels: Bruxelles-Nord, Bruxelles-Central, and Bruxelles-Midi (also called Brussel-Zuid). There are trains from Brussels to Louvain-la-Neuve every half hour and the journey takes between 30' minutes and 60 minutes depending on which station you depart from.
Timetables are available from Timetables of the Belgian Railways. When buying a ticket or checking for connections, please specify: "Louvain-la-Neuve". Simply indicating "Louvain" may take you to the flemish city of Leuven wich is 30 km from Louvain-la-Neuve!
From the train station walk up the street ("rue des Wallons") all the way through "Place des Wallons", "Place Galilée" and to the "Place des Sciences" (a place with wooden floor). The congress location is in the building on your left side.