How to use PluginTask to countdown.

I am wondering on how to use PluginTask to countdown from 30 and stop.
Example: Match starting in 30 seconds... and so on.

You can simply schedule a sync repeat task that runs every 20 ticks. 20 ticks = 1 second.
Store the counter in the task and when it reaches 0 cancel the task.

Example, please?

there is a lot of plugins that uses this. mind checking the sources instead? plus, next time, use the search engine provided above because i see lots of threads about this.