Grammar Corner is especially designed to help you learn and improve your English. The lessons are followed by different exercises and quizzes, so that you can easily check if you've understood everything.
Bear in mind that grammar is not just a set of rules, but a sort of aid, or tool, that helps you express yourself better, and also lets the others get the idea of what you're saying. When you understand the grammar of any language, you can grasp a lot of things yourself.