You will need a computer running Windows XP or later. This can be a Mac as long as you have installed a program like BootCamp, which partitions the hard drive and lets you install Windows on one side. Ideally you’ll also have a computer running Windows XP or later, with minimal distractions while training. 
The most important key to success, however, is what we call the IT (identified trainer). This may be the client, a parent or anyone who is organized and motivated enough to make sure the training sessions happen regularly. One session every week or two, or 4 in 2 weeks, then a week without, etc. is like going to the gym on that schedule. You won’t get results, you’ll get frustrated, and you’ll end up wasting your money. The IT should be someone who is comfortable with computers and ideally someone who can follow instructions. Finally, the IT should NOT be actively at war with the target client. Otherwise, the training just becomes another battle in the war, and it won’t happen. If you can’t provide these things, spend your money on a good trainer.