Regarding this $1000 start up money (seed capital), please code it as “equity” in your accounts.
This is not your income (revenue) for your business, so this is not taxable revenue for IRD when you file income tax return at the end of financial year.
If you want to invest more money in, please continue code this as “equity” in your accounting book.
This “Equity” will be shown on your balance sheet. I strongly recommend you use Xero software for your accounting software.
Regarding the shares – this requires you to register them with the company office and create a “equity shares” entry, so is slightly more complex and not required.