Just voting 1 above the line for your preferred party in the Senate means you don't get to choose your preferences, but filling out all the numbers below the line is fiddly. The Below The Line site comes to the rescue, letting you customise your preferences and print out a guide to take along on voting day.
After selecting your state, you can either nominate a main party and then your secondary choices, or assemble your own preferred order from scratch. Once you're done, you can print out the guide and even share your suggested preferences with others if you wish. You'll still have to fill out the ballot itself on August 21, but at least you'll feel confident of not making a mistake.