The work itself deals with trying to teach children between middle and high school. How good or bad that is depends on you. I found the older kids were eager to learn, but the younger kids were sometimes easily distracted and patience is needed.
They only pay you for the hour/two hours a day you spend teaching. Not any of the time you spend preparing the lesson. How fast you are at preparing a lesson is up to you as well. I should note though, they do give you a lot of material you can use to teach, and for a lot of the classes, the projects came with finished versions, making preparations easy. Still though, don't expect this job to only be an hour/2 hours per day of work.
Speaking of which, you won't be working that many hours a week with this job. 5-10 hour weeks are common, out of the 12 weeks I worked there was only two 20 hour weeks. That was fine for me, but obviously this is not true for everyone.