I hope you find our grammar site useful, but grammar is only one part of learning English, or any language. We also need to practise reading, writing, speaking, and listening, as well as learning new vocabulary and improving our pronunciation.
Ways to improve your English:
Read about improving your English listening here.
Read about improving your English reading here.
Read about English vocabulary and collocations here.
Read about improving your writing here.
Read about improving your English speaking here.
Read about using Anki flashcard software here.
Above all, don't panic if you can't speak or understand or write well yet!
It takes a long time to learn a language, and learning English might be particularly difficult (it depends on your first language). If you relax and don't force yourself, then it will come.