In NSW, the Power of Attorney Act 2003 has a prescribed form and process for the purpose of appointing someone as your attorney, whether as a general or enduring power of attorney.
You can obtain a copy of that on line or you can see a lawyer.
The decisions you will need to make when appointing someone as your attorney are:
Are you going to revoke any prior appointments?
Who will you appoint? Someone who has common sense and who you trust.
Will you appoint more than 1 person, in case something happens to one of them?
If you appoint more than 1 person, must they act together or can they act separately?
If you appoint more than 1 person, is their appointment substitutionary [their appointment depends on something happening to the others of them (eg death or disability)] or alternate [they can act immediately and separately from one another]?
When does the appointment start and end?
Does the appointment end if you lose your mental capacity through illness or accident? [ie will the appointment be an enduring appointment?]
Can the person you appoint use the appointment to give themselves a benefit?
Can the person you appoint use the appointment to give anyone else a benefit?
Can the person you appoint delegate their authority?
If the appointment is of an enduring power of attorney, it must be signed before a lawyer, barrister, clerk of the court (and others) and a required certificate given.