The philosophy is recognized as non-dualism, and has been around for a very long time in many of the major religions, but studied by only a few.
Basically, non-dualism dismisses the idea that everything can be judged as good or bad, sacred or profane, and so on. The purpose of the Course is to move beyond our tendency to hang a judgement on everything we see and do, thereby adopting a more peaceful attitude towards all.
The lessons are completed on your own, as you read and reflect on each daily lesson. It takes a fair deal of tenacity to keep going beyond the first 70 or so lessons, but even 30 lessons are well worth the effort, because of the personal changes experienced. It takes about 5 minutes in the morning and then again in the evening, for the first 30 lessons.Everything is available online.
Look here for a general introduction:http://www.acim.org/Lessons/index.html
Look here for the lessons:http://www.acim.org/Lessons/lesson.html?lesson=1
(I think there is some important advice on how to do the lessons, something like, just do them, and don’t worry about it seeming strange or silly.)If English is not your first language, search for the lessons in your native language, because they have been translated into many languages.
Let me know if you are having a problem because of my explanations.