coin countdown timer system for Arcade machine on arduino uno

hi i need help me for making a coin countdown timer system for Arcade machine on arduino uno and what is electronics parts i need for this projects thank you :)

freefox: making a coin countdown timer system

What is one of those?

yes i want to make coin countdown timer system for Arcade machine on arduino uno

I don't even know what a "coin countdown timer system" is, that's why I asked.