Back in 1921, Helen wrote "Now that I am older and a little better acquainted with the harp, maybe I should give the book (The Irish Harp Book) another look and try to learn from it properly. It always looked a bit overwhelming to me when I first bought the book."
I'm familiar with that feeling, but nowadays we have something to help, and that's recorded performances of thousands of tunes on the Internet. A song can look confusing on the page, but if you go to YouTube, ABC notations.com or TheSession.com and listen to it while reading the notes, the song can seem much easier to play.
And of course there are more sites than the three I just listed. But wait a minute - first search "name of song" recording