Also, something that I've found is that if you go wrong somewhere instead of mindlessly searching for the error (assuming there are multiple or you don't know the error's location) just start from the beginning and go down seeing that if this works. If you see a break and something disconnects, in all probability that's where the error is. It's all logic.
EdX is another leading online-learning platform that is open source instead of for-profit. It was founded by Harvard University and MIT in 2012, so you know that you’ll learn about cutting-edge technologies and theories. Today, edX includes 53 schools. You probably can’t go wrong with the free Introduction to Computer Science from Harvard University.