It is a really good book for you study English. In this book you can study how to speak English and many grammatical points of English language which are very important. This book is more than 40 mb, so it may take you a little long time to download. And the book is also designed for self-study. You can learn by yourself without any teachers to guide you because the book will be a teacher for you.
As Myanmar is a country neighboring Thailand, it is good for you to learn some basic Thai words so that you can meet a Thai friend and greet them or introduce yourself to them. Thus, you will be able to make a lot of new friends for your life which is good. As you might have already known, Thailand is not the country where English is widely used. As to my experience, very few people speak English in Thailand. And some Thai people really don’t like when you speak English language to them. They think English is the language used in Thailand just to persuaded tourists.