What to study before CELTA?

I am a non native speaker and will be taking CELTA at Gloucestershire, UK in September.I don't know much about the course.What the first few days are going to be like?
Although I have a lot of reference material but English is very vast and really don't know from where to begin.
I am brushing up grammar from Michael Swan (Practical English Usage) along with Jim Harmer's Text book.Am I moving in the right direction?
Please guide me about preparations I need to do beforehand?

What you're reading will be very useful. The course will be intensive and the first days particularly so. Start trying to think not just about what you're learning, but how you will actually deal with things in the classroom and what problems learners may face.

I'd email your course providers and ask them what the priorities are, they will certainly be willing to help and might even have a guide ready to send you. I'd recommend learning:
- Definitions of parts of speech (adverbs, determiner, etc)
- Names and uses of tenses
- The phonemic script

Here's a whole article of mine on the topic:
Preparing for the CELTA etc | TEFL.net

Thanks a lot:)

Could you give us a bit more understanding on the phonemic script please ?