How much is a house in Thailand?
How can I teach Englsh?
Are Thai schools good?
are rather tiresome, they are the how long is a piece of string? type question.
To be is of course the first thing that every teacher should know. I recently answered a question on another forum like this:
It's highly unusual for Native speaker TEFL teachers to be expected to teach absolute beginners. They will usually have received some instruction from their own language teachers or home room teachers.
Over the years it has been clearly demonstrated that the human brain is equipped with a grammar engine, and that it is not necessary (at least at elementary levem) to teach grammar as a stand-alone subject - it does not appear that you are trying to do this anyway, but I am just pre empting other readers questions.
To be is the most fundamental element of any language and the first thing which is taught and learned. It receives excellent treatment in all course books - right at the beginning - Any attempt to explain it on a forum, is IMHO, superfluous.
Dig into your Oxford Practice Grammar (OUP) Unit 7 or your Murphy Essential Grammar (CUP) Unit 1 and take it from there. Failing that, refer to the course book you are using, and if that still does not work, look back to your own teacher training notes.
If all else fails (you don't need to be a linguist to do this), learn the equivalent in your students' language and make an analogy to that. I remember many years ago that on the afternnoon of the first day of my arrival in Thailand, I learned to say , without any effort, phen kru krap - I am a teacher!
Oxford Practice Grammar, Eastwood 1991, 1999, Oxford University Press ISBN 0-19-431369-7
Essential Grammar in Use, Murphy 1990, 1998, Cambridge University Press ISBN0-521-55928-6