Here's a good tutorial on fixing scratches on a glass or ceramic stovetop: https://homeguides.sfgate.com/fix-scratched-glass-cooktop-27383.html
If they're just simple surface scratches this works for me. Spay on some hydogen peroxide then sprinkle a light layer of baking soda on top. Let it sit over night. Wipe it clean w/a wet rag in the morning.
Use automobile compound. Apply let it dry and wipe it off with a microfiber cloth