First off, Aphex Twin is one guy, Richard D. James.
As a novice, you probably want the Richard D. James Album, which is his most approachable record, I think. Some of his stuff is hard to get into if you're not used to it, but you should be ok with this.
I Care Because You Do is another good choice, slightly less... normal, for lack of a better word, but a lot of people consider it his best work. My opinion on that varies.