Regardless of the time of day you decide to fly, the ticket price will remain around the same. Book flights from Brisbane to Windhoek as you normally would.
For a flight from Brisbane to Windhoek, you will be flying from Brisbane. Brisbane (BNE) is just 12.3 km from the centre of the city. Brisbane is the only Brisbane airport and it handles 0 outbound flights to Windhoek per day. 1 airline has flights to Windhoek from Brisbane on a regular basis.