Thanks for your reply. I am running littleBits and the Ardunio IDE on an iMac with OSX El Capitan (10.11.1). Right now, I have the power module with battery and the processor board connected to the USB port. The power board is shut off. I am going through the the Getting Started with Arduino procedure (Getting Started with Arduino), and expect to have further results (or lack thereof) to report in my next post.
I have Arduino Leonardo, version of Arduino IDE not given, but presumably, it is version 1.0.5 offered at the web page: Getting Started with Arduino. One overriding problem seems to be that the IDE offers only a Bluetooth Port, not a serial port. While it would be interesting to me to establish the connection over a Bluetooth Port, I need to learn how to activate the Serial Port first. (I would probably need a module with Bluetooth capability anyway).
Many years ago (maybe 30 years ago?), I worked with Motorola 6800 series microprocessors, and was used to having extensive listings of hexadecimal instructions. Probably a topic for another forum, but it will give you a little more of an idea of my background.
Microprocessors in general interest me; the very study of them seems for me to be enough of a justification for me to work with them. However, I have also considered the possibility of using them to control signaling and lighting on my model railroad layout. After that, who knows what other applications I may be able to develop.
Anyway, I will proceed with the basic set up, and welcome any further feedback you may have based on the information I have thus far presented.