After importing the addon into a world, do '/function start' to add the objectives it needs to execute. Then do '/function time/tick' to officially begin using the addon. 

The key that you need to freeze time is a clock. By dropping a clock from your inventory, you get a cool effect of the world suddenly turning dark and bright again, showing that time is beginning to stop. The clock will float in the air and stop every entity or mob except players for five seconds. Once the five seconds are over, time begins to move forward again and the clock that you used is cleared out of reality. 

There is however an exploit or a glitch in the matrix to abuse time. If you can grab the clock before it disappears after five seconds, time is permanently frozen. You can take advantage of this to create cool sceneries. 

There are two ways to stop time from being frozen eternally, you can throw the clock again to continue time. Or you could do '/function end_clock' which will also stop time from being frozen. The concept was inspired by the famous anime 'Jojo's Bizzare Adventures'.