Permission should always be sought to access water through private property. Always be polite and respectful of property owners and listen to their requests. Do not leave rubbish or litter behind. If you can bring it in, you can take it out.
A recreational fishing licence is required to fish in NSW. Relevant information can be found here https://www.service.nsw.gov.au/transaction/apply-recreational-fishing-licence.
The size limit for both brown and rainbow trout is 25cm at the time of publication. There is a daily bag limit is 2 fish per person per day and an overall possession limit of 4 trout per person. More details can be found here http://www.dpi.nsw.gov.au/fishing/recreational/fishing-rules-and-regs
Only two bass can be kept per person. There is no minimum length for bass but only one over 35cm can be kept. Total possession is 4 with only one over 35cm. Further information on lengths and bag limits can be found here http://www.dpi.nsw.gov.au/fishing/recreational/fishing-rules-and-regs/freshwater-bag-and-size-limits