How to multitask in iPad OS26

Hi all,
I have recently returned to iPad, and have an iPad Air M3 running iPad OS 26. I'm keen to explore the new multitasking options, but can't for the life of me figure out how! I've made sure the multitasking option in settings is set to stage manager, but can't figure out, when I have an app open, how to then open another app in a new window, and have both on screen simultaneously.
Any insight you can give is much appreciated :)