I give all credit to NashBoss100 for the original design and coding for this project. Here is a link to his post https://www.hackster.io/Nashboss100/arduino-airsoft-time-bomb-with-button-speaker-and-3-leds-83c230.
I wanted to make this, and I did, but I needed help because it was not easy to understand the schematics. I tried to make the schematics easier to understand, and I changed some wiring and added a 9V battery with a switch(I used a light switch). In addition, I edited the code to make it last roughly 10 minutes instead of 1. The defuse button can only be used after 20 seconds.
I updated it to 'Beginner', because I was able to make it, and I have never even heard of Arduino or used Arduino UNO before.