My restart button isn't doing what I need it to do.

I'm pretty new to Unity so I'm not very inclined on C# scripts and how to connect everything using code. I recently wanted to expand my knowledge and complete one of the tutorials, and I made the 2D UFO game. However, I wanted to go even further and add my own enhancements, I successfully added a timer and restart button to the game. The restart button shows up, but when I click it, it doesn't reset the scene (the "pickups" and the player). Any help is appreciated, thanks!