A snapshot is taken automatically when an account's history is attempted to be viewed for the first time. Once this has been done, it will be updated every few hours for the first week, and then a schedule will be created to ensure their data is checked at the optimal time every day.
Snapshots can be viewed in four different ways: /<game> daily , /<game> weekly, /<game> monthly, and /<game> from.
/<game> daily will show the change in the player's statistics from the oldest snapshot taken in the past day. /<game> weekly and /<game> monthly work in the same way, but for the past week and month respectively.
However, /<game> from is a special case. This command allows you to view the change in statistics from an arbitrary period in the past. It will find the closest snapshot taken to the time specified.
For example, /<game> from weeks:1 days:3 hours:14 will find closest snapshot taken in the past 1 week, 3 days, and 14 hours.
For information on more advanced tools for viewing snapshots, check out the History section.