It might also be a good idea to do a little practicing before moving on. It may be a good idea to redo one of the later projects from our fundamentals course such as the calculator or rock-paper-scissors. If you want something fresh to work on, now would be a fine time to do some coding exercises from across the net. The following sites are all great places to look.
A quick web-search on the topic will be more useful than any explanations here, and if you still want to learn it (many older codebases still use it, and you will see it on many older Stack Overflow posts) we are confident that you can pick it up quite easily by reading the documentation on their website.