The length of study depends on your foundation. If you have the corresponding foundation of ps and css, it will be faster and easier to learn. Generally, it takes about 4 months to learn web design from zero foundation. If you want to study systematically, you can go to some training institutions, such as Star Lion Creative in Shenzhen. If you want to teach yourself, you can look at their web design outline, learn more about it yourself, go to some cool websites at home and abroad and download some design materials.