RedFox2046

I really want to setup an event on a server and I need a Countdown to do it, I want to use OpenComputers to do it but I don't know how I would need it to look like this "00:00:00:00" and I want it to be days:hours:minutes:seconds. Also if it his 0 it should send a redstone signal out from the computer. I'm a novice at coding so it would help a lot if someone could make it for me or send me to someone who has already done it so I can use it and learn more about code. Thank you in advance.