just want to know how you proof your financial support (cost of living for 3 months) under JSV?

it requires me to provide following :
- Air ticket to NZ (Ticket Bought) <- just print the e-Ticket?
- Sufficient fund for return air ticket <- how to proof I have funds
- sufficient financial support for 3 months in NZ <- how can we proof it? Just print out bank statement and require bank officer signatory?

Please assist me how can I provide the proof the above ?