As an Emacs user, how do you handle working with multiple projects at the same time?

Hi, I'm a emacs newbie, and one of the things that been giving me a lot of frustration, is how to handle working multiple projects in the same window? Before I was using PHPStorm for coding in several different languages and projects at the same time, and I would have one phpstorm window per project. How do you handle this in emacs, since the main idea behind emacs is that you use one window for everything. What is the best way? Just split screens?

Thanks