Animate Stills

Hi there,
I am new to Fusion and want to try this;

Could anyone point me to a tutorial?
I have my source Media (a JPG) in the flow, after that I go to a Merge, which has a Poly Mask connected to it, but I am already stuck at isolating (substracting) my Matt from the souce still.
Thanks for help
I am new to Fusion and want to try this;

Could anyone point me to a tutorial?
I have my source Media (a JPG) in the flow, after that I go to a Merge, which has a Poly Mask connected to it, but I am already stuck at isolating (substracting) my Matt from the souce still.
Thanks for help