C is arguably the most popular programming language in the world. It is vital for certain operating systems and is considered one of the most effective ways of improving knowledge about algorithms. The Programming Course in C is available on YouTube and was created by Carl Herold. There are 13 episodes in total broken down into 66 manageable videos. You will learn about functions, program flow, algorithm design, data structures, printing binary data, booleans and bitmasks and so much more!
There are multiple free courses on offer on the Android focused Developer page. With the course: Android basics in Kotlin you will learn the fundamentals of Kotlin programming and about creating simple apps with Android Studio. There is then a more advanced course in Kotlin. Beyond Kotlin, there are courses in the fundamentals of Java, and also advanced courses in Java. These courses should help you establish a solid foundation before moving on to more advanced programming.
If you are interested in creating a website, then an understanding of HTML and CSS code is essential as they form the basic building blocks of many websites. This HTML and CSS course on Udemy is a great one for beginners looking to learn quickly. There is a total of 5h50 of on demand video tutorials. An added bonus from this course is that you can receive a certificate upon completion of the course.
HTML5 is the latest version of HTML, the basic language used by the 'World Wide Web'. Mastering it takes time and practice, much more than just watching a YouTube video. You can however learn the basics and get started with this free HTML5 course on YouTube that has over 1.2 million views. There are 147 chapters pinned in the comments section so that you can easily navigate the considerably long 11h30 video.