When you get here
Some supervisors prefer to throw you in at the deep while others plan your project so that you get a gentle start. What suits you depends on your past experience and how ambitious and adventurous you are, and many problems can be averted if you express your needs clearly. You may be the type who likes to get on with research without too much fostering; alternatively; you may prefer a degree of mentoring and assessment that some would find suffocating. Whatever the case, during the course of your PhD you'll find a level which suits both you and your supervisor.
Also remember, your supervisor isn't the only one who can guide you - postdocs and other scientists in you division can also be a great source of protocols, advice and expertise) especially if you are working in an area that is also new to your supervisor). Most importantly, never allow yourself to be drustrated or unhappy - look for help before this happens!