If you dont know or havent bookmarked the login URL for your school the easiset way to login is simply goto the public website https://sisat.com.au and click on the school Login Button
Then Start typing the name of your School select it and it will direct you to your school login once there you can simply bookmark it.
or another alternat way to login is is use your school number.sisat.com.au for example 5072.sisat.com.au replace the 5072 with your school number