The sports templates each include a Score Bug, which include a clock that can be made to count up. Here are the steps to trigger the clock in the bug to count.
- Add the Score Bug to your playlist
- Set Clock Offset and Clock Duration to the values you want (of course the defaults here may be fine)
- Uncheck the box that says "Clock Running"
- Copy the current time into Clock - Time Zone Sync, in the "Unix Epoch" format, accurate to milliseconds. You can get this value from various sources but one good example is https://currentmillis.com/.
- Now take the bug to air. The next two steps, do when you are ready to trigger the clock running.
- With the bug on air, check "Clock - Running"
- Now press "Update Page"
- Your clock should start counting up!