Hello Jannatia,
I'm not sure what you're asking but I'll try to help anyway. As far as making custom animation for AO. I don't thing you can. But if you want to make custom dance scripts. Then there is a very handy tool for that. It's called AO Scripter.
Click here to go to the download page. It was made by the nice folks in Unity of the Rose. A very old AO org.
It has a lot of great features and you don't have to be a computer expert to use it. With it you'll be able to make your own scripts very easily. Just remember, if you want a script to loop. Make sure the last line is / followed by the script name. You'll need a "stop" that you can get by downloading dance scripts we have here.
Hope that helps. Have fun