I require teacher training to start a business. Is the training tax deductible? If so, what are the steps? Do I need business number set up before I do the training?

I have a business number from when I did contract work a number of years ago and was going to change this number over to the new business that I am thinking of doing.  I am wondering if I need to do this before I do any training that is required for the business? Also, I require the training in order to run the business, provide a service to clients.  Is the training itself tax deductible even though I am doing the training before I am making any business revenue? If so, what are the steps needed to do so?