Suppose we want to drop data for the first 12 hours of 2015-09-12 and keep data for the later 12 hours of 2015-09-12.
Go to the [datasources view](http://localhost:8888/unified-console.html#datasources) and click the blue pencil icon next to `Cluster default: loadForever` for the `retention-tutorial` datasource.
In the upper rule box, select `Load` and `by interval`, and then enter `2015-09-12T12:00:00.000Z/2015-09-13T00:00:00.000Z` in field next to `by interval`. Replicas can remain at 2 in the `_default_tier`.
In the lower rule box, select `Drop` and `forever`.
Now click `Next`. The rule configuration process will ask for a user name and comment, for change logging purposes. You can enter `tutorial` for both.
Now click `Save`. You can see the new rules in the datasources view:
Give the cluster a few minutes to apply the rule change, and go to the [segments view](http://localhost:8888/unified-console.html#segments) in the Druid Console.
The segments for the first 12 hours of 2015-09-12 are now gone:
The resulting retention rule chain is the following:
The rule chain is evaluated from top to bottom, with the default rule chain always added at the bottom.
The tutorial rule chain we just created loads data if it is within the specified 12 hour interval.
If data is not within the 12 hour interval, the rule chain evaluates `dropForever` next, which will drop any data.
The `dropForever` terminates the rule chain, effectively overriding the default `loadForever` rule, which will never be reached in this rule chain.
Note that in this tutorial we defined a load rule on a specific interval.
If instead you want to retain data based on how old it is (e.g., retain data that ranges from 3 months in the past to the present time), you would define a Period load rule instead.
