Just use your (or ask if you can use your parents) library card
Go to the State Library website www.slwa.wa.gov.au
Click on the menu item How Do I Find
Scroll to eresources
Click on eresources at home for Public Library Members
Scroll down to Encyclopedia Britannica Library Edition Online and click on the link
Follow the instructions to choose your local government area and then insert your library card number.
There you go!
When you have finished have a look at the other material available in the eresources section of the State Library Western Australia website.