Due to the difficult situation in the hotel sector, it was not easy to reserve large room contigents for the participants of the meeting. Thus it is recommended to reserve these rooms from the contigent early (see table below):

An other option is to directly contact the hotels or guesthouses from this website: 
https://www.steiermark.com/de/Erzberg-Leoben/Urlaub-planen

or any other booking-app of your choice.
Also hotels or guesthouses in  Bruck, Proleb, Niklasdorf, St. Peter Freienstein, and Trofaiach can be used because of easy and frequent bus or train connections.