The basic rules are similar to cricket, but have weird local additional rules.
If you hit the ball into a window, car, fruit tree or over the back fence you are called out. If you hit the ball with a glancing blow you must run (also known as tippity). It’s polite not to spend too much time at bat, so after making a certain score you should hit the ball towards players so they can catch you out. And a heap of other rules that vary from backyard to backyard 😀
BBQ on Australia Day, somewhere that you can go swimming is preferable because it’s around the hottest time of year. Listening to Triple J hottest 100 in the background at this gathering is also pretty popular.
Christmas is for catching up with family, but Boxing Day is for friends.