How do I run an APEX program?

Excuse me, could you please explain to me how exactly one goes about running an APEX program? I've heard it's quite powerful and efficient, but I'm a bit lost on the specifics of the process. Is there a certain software or platform that's required? Do I need to have any prior knowledge or experience in a particular field? Any guidance or tips you could provide would be greatly appreciated. Thank you in advance for your time and assistance.