Pre-approval: a lender agrees in principle how much it will lend, subject to conditions. It gives you a budget and the confidence to make offers.
The offer: most offers are conditional, for example on finance, a builder's report and a LIM report from the council. Have your lawyer check the agreement before you sign.
Finance confirmed: the lender reviews the property, sometimes with a registered valuation, and gives formal approval. You then confirm your finance condition by the date in the agreement.
Unconditional: once every condition is met, the sale becomes unconditional and the deposit is often paid at this point.
Before settlement: you sign the loan documents with your lawyer and arrange house insurance, which lenders require from settlement day.
Settlement day: your lawyer receives the loan funds and pays the seller. The keys are yours.