You can choose one of the 2 options to set up the countdown duration.
This option is best if you don't have a specific end date in mind, and you just need to run a countdown for a specific period of time.
For example: You need to run a 15 mins countdown before you start your live show. Once you press Go Live, your countdown will start ticking down exactly for 15 mins.
This option is more convenient when there's a specific time or a deadline for when your countdown needs to end.
For example, if you have a countdown to the end of SALE, setting the end date will be more convenient.