Khoi,
Please do not hijack threads. When you want to post a new question, go to the Home page, select the appropriate forum, then create a new post.
1. You cannot save an individual registration button. You save all 8 in a file. Just press the J button, and you’ll see a Save menu item. Name your file something appropriate. Most of us use the song title as the file name.
2. When the OTS link is turned on, pressing a variation button also loads its OTS. If the link is off, pressing a variation button only changes the drum pattern; if you want to change voices, you press your desired OTS button yourself.
3 ART buttons are for SuperArticulation voices. They activate a special feature of the voice, like a breath in or out. When you have a voice where these buttons light up, just press one of the buttons and see if you like what you hear.
Cheers,
Fred