Below is the map of Observatory. Guest house is located by number 11 on the map.
Getting there:
The best (and almost only) way to get to Observatory is to take a taxi from Airport/Yerevan. To get a taxi either use Yandex taxi or gg taxi for cash, card MIR, or bank cards issued by non-Russian banks. Visa and Mastercard issued by Russian banks don't work. Taxi price is around 2000 dram to Yerevan, and 6000 dram to Byurakan.
Hotel:
Participants are staying at guesthouse (11 on the map above). Organizers will meet participants from 4pm on Monday, June 6 at the entrance of Byurakan Observatory complex.
Some useful tips:
(1) Cards MIR work in the most places, ATMs. Visa and Mastercard issued by Russian banks don't work.
(2) SIM cards with mobile data are available in airport.
(3) There is an ATM in Byurakan city center.
(4) The exchange rate in the airport is quite high. There are places with better exchange rate in Yerevan, which accept USD, EUR, RUB.