I'm trying to make a simple theremin project with the Elegoo Uno R3 following an online tutorial (link in comments), but there's an error of "redefinition of 'void setup()'", I'm pretty sure
Theremin World - Open.Theremin.UNO Progress Report
6 Project "Light Theremin" Arduino StarterKit- Constant, high steady tonee of - Project Guidance - Arduino Forum
Project 06: Light Theremin – Programming in Arduino
Learn how to make a simple Theremin with an Arduino and an LDR sensor! - The Nerd Musician