OOP being one of the more abstract things you will encounter while working with Processing, but definitely something you want to tackle, if you ever want to write sketches similar to the one you mentioned. Additionally, everything involving movement will become easier and far more flexible, if you are working with vectors. Again, this may be another thing you want to tackle, after you have laid down the basics. Fortunately, Dan has great tutorials on both subjets, check them out here (OOP) and here (Vectors).

To get going, I can also highly recommend you check out the Fun Programming video tutorials, which start at the very simplest and gradually work their way up to intermediate and complex sketches. 

Happy Coding!