Or use nestopia or some other emulator that has lua script

Nestopia doesn't run Lua.

You just put the script wherever you want, then open a new script window, assuming that you are using FCEUX, and run the script. Make sure you start the game as fast as possible though, or else the timer will start wrong.

when I put it I throw an error that says "Lua run error"

also make sure ur using single cart