Classes are going on at various times and this depends on the exact class. Many classes consist of several sessions so you’ll want to make sure to start with the first session of each class. The full schedule is available on the Events page. You can also see the available classes listed by topic on the Classes page.
Some classes are designed to be taken together in order. That’s because the earlier classes explain skills that you’ll need in order to understand the later classes. The Essential 42 classes are like this. They show you how to code from step one when you still need to get your computer setup for coding.