diff --git a/docs/interacting/bydbctl/schema/top-n-aggregation.md b/docs/interacting/bydbctl/schema/top-n-aggregation.md
deleted file mode 100644
index a6b4e70ec..000000000
--- a/docs/interacting/bydbctl/schema/top-n-aggregation.md
+++ /dev/null
@@ -1,20 +0,0 @@
-# CRUD [TopNAggregation](../../../concept/data-model.md#topnaggregation) on the Web UI
-
-CRUD operations create, read, update and delete groups.
-
-The group represents a collection of a class of resources. Each resource has a name unique to a group.
-
-[bydbctl](../bydbctl.md) is the command line tool in examples.
-When you in the `Measure` tab, you can view the list of top-n-aggregations in the specific group.
-
-![top-n-get.png](https://skywalking.apache.org/doc-graph/banyandb/v0.7.0/web-ui/top-n-get.png)
-
-## Create Top-N-Aggregation
-You can create a new top-n-aggregation by clicking the right button of the mouse on the `Top-N-Aggregation` category and select the `new topn-agg` button.
-
-![img.png](https://skywalking.apache.org/doc-graph/banyandb/v0.7.0/web-ui/top-n-add.png)
-
-## Update/Delete Top-N-Aggregation
-You can click the `edit topn-agg/delete` button on a specific top-n-aggregation to modify/delete the top-n-aggregation:
-
-![top-n-edit.png](https://skywalking.apache.org/doc-graph/banyandb/v0.7.0/web-ui/top-n-edit.png)
\ No newline at end of file
diff --git a/docs/interacting/deleting-data.md b/docs/interacting/deleting-data.md
new file mode 100644
index 000000000..7a0b1b06a
--- /dev/null
+++ b/docs/interacting/deleting-data.md
@@ -0,0 +1,52 @@
+# Delete Data in [Measures](../concept/data-model.md#measures) and [Streams](../concept/data-model.md#streams)
+
+Due to the design of BanyanDB, the `Property` data provides [CRUD](./bydbctl/property.md) operations,
+but the data in the `Measures and Streams` can not be deleted directly.
+The data will be deleted automatically based on the [Groups](../concept/data-model.md#groups) `TTL` setting.
+
+The TTL means the `time to live` of the data in the group. 
+Each group has an internal trigger which is triggered by writing events. If there is no further data, the expired data can’t get removed.
+
+For example, the following command will create a group with a TTL of 7 days:
+```shell
+bydbctl group create -f - <<EOF
+metadata:
+  name: sw_metric
+catalog: CATALOG_MEASURE
+resource_opts:
+  shard_num: 2
+  segment_interval:
+    unit: UNIT_DAY
+    num: 1
+  ttl:
+    unit: UNIT_DAY
+    num: 7
+EOF
+```
+The data in this group will keep 7 days.
+
+If you want to change the `TTL` of the data in this group to be 1 day, use the command:
+
+```shell
+bydbctl group update -f - <<EOF
+metadata:
+  name: sw_metric
+catalog: CATALOG_MEASURE
+resource_opts:
+  shard_num: 2
+  segment_interval:
+    unit: UNIT_DAY
+    num: 1
+  ttl:
+    unit: UNIT_DAY
+    num: 1
+EOF
+```
+
+More ttl units can be found in the [IntervalRule.Unit](../api-reference.md#intervalruleunit).
+
+You can also manage the Group by other clients such as [Web-UI](./web-ui/schema/group.md) or [Java-Client](java-client.md).
+
+## The API reference 
+- [Group Registration Operations](../api-reference.md#groupregistryservice)
+- [ResourceOpts Definition](../api-reference.md#resourceopts)
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diff --git a/docs/menu.yml b/docs/menu.yml
index ccdf60f6d..ca0fc5aa5 100644
--- a/docs/menu.yml
+++ b/docs/menu.yml
@@ -94,6 +94,8 @@ catalog:
             path: "/interacting/web-ui/property"
       - name: "Java Client"
         path: "/interacting/java-client"
+      - name: "Deleting Data"
+        path: "/interacting/deleting-data"
   - name: "Operation and Maintenance"
     catalog:
       - name: "Configure BanyanDB"