If you have been charged with a crime you should contact a solicitor immediately. Typically, your solicitor will tell you that you have a right to silence and will tell you to refuse to answer any questions from police. The right to silence literally means that you do not have to say anything, give information or answer questions. Even if the Police ask you a direct question, you have the right to not answer it.
Police will typically ask you questions about whether you were at a location at a time, whether you recognise someone in CCTV footage, and what you were doing at a particular time. The right to silence means that if you refuse to answer, police cannot assume your guilt as a result of your silence.
There are some exceptions and modifications to the right. Exceptions to the right to silence include where police ask for your identification- i.e. name and address- where they have the right to do so. Also, if your car was involved in a serious crime then you are obliged to give the police details of the driver and any passengers at the time of the offence.
These days, thanks to s 89A of the Evidence Act 1995 (NSW) your solicitor may refuse to come and visit the police with you in relation to an offence that you have been, or are at risk of being, charged with.
Before the introduction of s 89A, police would issue a general caution that anything you say could be used in evidence against you and they would tell you that you have the right to remain silent. Since 1 August 2013 and pursuant to s 89A, police can now give a special caution in certain circumstances.
When police give you a special caution they will tell you that a) you do not have to say or do anything, but it may harm your defence if you do not mention something when questioned that you later rely on in court, and (b) anything that you do or say be used in evidence. This means that, after receiving the special caution, by remaining silent, you may jeopardise your defence in court if you fail to mention things you rely on during questioning.
A special caution may not be given unless you are accompanied by a solicitor who is acting for you. As a result, solicitors will often refuse to come to the police station and will prefer to give you advice over the phone.