I decided to make a video on how to input aleatorics, since it's super fiddly and if anyone were to want to use it in their composition they would have to learn how to do it. It was great to see that the first video that comes up when I google "aleatorics on sibelius"was from our very own Sam Xu! But it wasn't quite what I needed as she only included non-rhythmic aleatoric cells. I covered rhythmic aleatoric cells, staggered entires, transition into metred music, and cells without rhythm.
One thing I've learnt about Sibelius: it has very few, and very thin arrows available! However, I did like the bracket I was able to put over the top to count the seconds.