"I have long been struck by the contrast between the success with which the adventurous learn APL by simply using it, and the frequent failure of lecture courses to communicate the simplicity and applicability of the language."
Kenneth E. Iverson, 1981 - A Working Introduction to APL
Some of the best resources for somebody new to APL and programming in general are:
- The Learn tab on TryAPL
- The book Mastering Dyalog APL by Bernard Legrand
- The APL Cultivation Stack Exchange Lessons
- The Zark APL Tutor
Follow one or a couple of these tutorials through and play around a bit. To learn APL the advice is similar to that for learning other languages: have a goal (something you want to accomplish) and try to do it. Along the way you are sure to come across the pitfalls and gotchas of the language, and with time you may come to understand what APL thinking means.
If you get stuck, don't hesitate to ask your questions on the APL Orchard chat room.