Onscreen fire button for FPS games.

Hi, I'm hoping to modify unity's existing first-person controls with touchpads to include a fire button, so that onscreen the user has two touchpads and then somewhere on screen is a fire button.

Also, If someone were kind enough to help me reverse engineer the touch controls provided I would greatly appreciate it! I'm VERY new to unity.

ultimately, I'd love to replicate NOVA's control scheme.