Youtube has many nice (and free) tutorials to get you going. You can just type something like the language or technology you're interested in learning and many videos will appear, such as "How to make a website - beginner tutorial", or "How to make an app". or "How to learn backend development". Then once you know the basics for what you've chosen, try to start working on a portflolio of projects that you can then add to your Github and that you may even be able to send to future employees to show them what you know.
Another advice would be look at coding classes that are offered - if you are more of a self starter, learning from places like Udemy will be good or you can sign up for classes. Besides that, keep your eyes and ears open for opportunities over for internships, hackathons or other similar competitions & related summer programs.
Look into taking AP classes in computer science. Take college level classes at high school if your high school offers it. Upon completing try to tutor in Computer Science to other students if you feel comfortable.
Baljit recommends the following next steps: