The timer was made with a defined variable ($time) and using the command "(live:)[]"
"(live:)[code goes here]" will update whatever you code inside of it after every unit of time (e.g. (live: 1s) will update every second).
This is pretty much what I did:
(set: $time to 90)
(live: 1s)[(set: $time to it - 1)]