If you’re looking to get back into it, the is surprisingly easy to set up on an emulator or a homebrewed 3DS/DSi. It’s still the most intuitive "baby's first animation" tool ever made.

Since Flipnote Studio was officially discontinued and can't be downloaded from the eShop anymore, getting a ROM is the standard way to keep the community alive.

: Users could record sound effects or music using the system microphone to bring their animations to life. Flipnote Hatena

The software encourages users to experiment and try new things, with a focus on creative expression and storytelling. Users can create complex animations with multiple pages, or simple ones with just a few frames.

If you are looking for a specific on the animation style or a coding specification for a project, I can look for more specialized developer documentation. Are you trying to run the software on a specific device, or are you developing a tool that interacts with the files?