Please help me with Capcom Marvel Superheroes inputs

Hey so I don’t have much experience with 2d fighters but I’m really enjoying the Capcom games. Obviously, I’m not very good but after searching far and wide in the internet I still can’t use super moves or use any of my characters infinity stones in game. Is it a skill issue or is the r36s not registering my inputs right? I don’t suppose someone can confirm what the inputs should be? Hope this makes sense.

Apparently a gem can be activated by simply press LIGHT PUNCH + HEAVY PUNCH at the same time but doesn’t seem to work.

Thanks