How did a Roman legion prove that someone was worthy/actually won a mural or grass crown?

Question

Mural crown: First man over the walls during a siege of a fortified settlement.

Grass grown: Rarest and most prestigious award in Rome’s military history, awarded to a man who single handed-idly saved the army through his actions and could only be made/given by soldiers, not commanders

In: 74

Answer 1

The same way we do modern awards like the congressional medal of honor, or bronze/ silver stars. Someone that stepped up in the face of immanent danger to go above and beyond the call of duty. These were then, as they are now, witnessed by brothers in arms, and reported up the chain of command.