Generally speaking you can move into the accommodation booked on the Sunday before the commencement of the course; you will leave again on the Saturday after the end of the course. Should you wish to arrive earlier or leave later, at most schools you can book extra night(s) (against extra payment).

Yes indeed it is possible to book a course only. The prices for such courses without accommodation are to be found under the heading ‘Prices’ on the website under the school in question.