How to use Synthesia?

I want to create music videos and piano tutorials for my students. I have seen people using Synthesia on youtube. Any Tips or resources on how to use it?

 

Any help would be appreciated! My Purpose behind asking this question is that, Synthesia is a popular online tool to practice music for kids, but I have seen people creating online youtube tutorials using Synthesia.

For instance, a tutorial like this. I had hired a junior teacher who had experience in the techy stuff and video editing. He created this video for me. And now he has quit me and I am confused to how he used to do it.



I hope you understand what kind of tutorial, I am talking about here. My Goal is to ensure that I am able to record both hands separately. I want to create separate tutorials on how to play piano chords, using both hands including finger positioning and stuff.

Any friendly advice or experts who are already doing this using Synthesia. If I am posting in the wrong sub forum please direct me to the correct one, I am very new here.

Thanks.