I booked a ticket from Australia to Beijing ( I am Dutch) Do I need a Visa? If so, Which website can

If your final destination is Beijing and you want to stay there for more than 3 days, you need to apply for a tourist L type entry permit for that.
But if you will fly to a third country or region rather than Australia after staying in Beijing for not more than 3 days, you can enjoy the 72 hour free transit there. If so, no entry permit will be required.