This guy's website has helped me. he and his wife are deaf, so I think he'll probably give more accurate information than you might find other places, and he answers questions for people on ASL on his page as well. I've heard (from him) that ASL textbooks are actually pretty inaccurate oftentimes. They change the language to make it look stranger to English speakers so that it will look more "foreign" for the sake of marketing.
Also, if your story is set in Ireland, they would probably have a different sign language, as they aren't universal.
https://www.lifeprint.com/asl101/pages-signs/d/doctor.htm