To winterize your system, first you will have to blow out the sprinkler. You can look at this video to find some useful information. https://www.youtube.com/watch?v=s3YRbJYmvgA&t=99s
This video mentioned that you will have to turn on the sprinkler, so you can use the instant manual run feature in the home page to manually start watering for each zone to make sure all the water is out of system.
Then you should put Sprite in "paused" mode just in case some one (for example the kids) accidentally starts a manually run from the app. To put Sprite in "paused" mode, you can go to Settings->Controller->Enabled.