The above bookstore used to sell--and might still sell--a book called The Book of Hours or the Order of Common Prayers of the Armenian Apostolic Orthodox Church: Matins, Prime, Vespers, and Occasional Offices
. It's a white book and the version which I have was printed in 1964, by Ouzoonian House, in Evanston Illinois. It has these offices in it, translated into English.
I don't know of any online version.
As for exactly what was going on in the service you attended, I really don't know. The parish I go to really only has Vesper services during Lent. I would have to have been there with you to see and hear it myself and the explain it all to you. Maybe vasnTearn could tell you what was happening.