There is no official conference hotel, but many of the attendees will be staying at the Mespil Hotel (right across from the Canadian Embassy, as chance would have it). This hotel is located between the downtown (about a 15 minute walk) and UCD, with a direct bus going to each from in front of the hotel (the 39A or the 46). Rooms at the Mespil are bookable now with reference “UCDA240419.” The rate is 145 euro (including breakfast). Bookings must be made directly through the hotel by e-mail at firstname.lastname@example.org or by phone on 00 353 1 488 4600.
Another more affordable option is The Hampton, in close proximity to The Clayton, and also on the bus route to downtown and UCD. https://www.hamptonhotel.ie/
There are also an abundance of AirBnbs throughout the city. UCD is approximately 20 minutes from the downtown, so be mindful of the distance when selecting your accommodations. For the sake of safety, I would recommend only using “Super Hosts” (those with many excellent ratings) when searching on the AirBnb website.