What is the right approach in learning html, css and javascript for website developement? [closed]

I want to make a career in web app development. So I'm starting with websites. I have learned HTML, CSS, and relevant topics of javascript. But when I get to implement those and make a website on my own I get very confused and tend to forget everything and it all becomes chaos and I end up leaving that project there. So, my question is, is there any proper method of learning this? What am I doing wrong? Please, anyone, suggest me this.