HOW VIDEO SYNC IN MUSESCORE ?

Thanks for the kind words! The details of what requires Pro and what does not keep changing, and none of us over here on musescore.org (where we support the software itself) really know much about that, so best to ask that over on musescore. But I can tell you I used "Manage Audio Sources" which is one of the items in the "..." menu on musescore.com toward the upper right while viewing my score on musescore.com. You specific a video you want to use, then an interface pops up that lets you click while the video plays so the system knows where the move the cursor to the next measure. That's pretty much all there is to it.

Better ask that over at musescore.com, see also https://musescore.org/en/faq#faq-20657