fix(explorer): When to use host.docker.internal with InfluxDB 3.

- Revises guidance in install and get-started.
- Adds Explorer to project compose file for testing.

compose.yaml

@@ -369,6 +369,18 @@ services:
         target: /var/lib/influxdb3/plugins/custom
     secrets:
       - influxdb3-enterprise-admin-token
+  influxdb3-explorer:
+    container_name: influxdb3-explorer
+    image: influxdata/influxdb3-ui:latest
+    pull_policy: always
+    ports:
+      - 8888:80
+      - 8889:8888
+    command:
+      - --mode=admin
+    profiles:
+      - explorer
+      - influxdb3
   telegraf-pytest:
     container_name: telegraf-pytest
     image: influxdata/docs-pytest

content/influxdb3/explorer/get-started.md

@@ -36,9 +36,26 @@ InfluxDB 3 Explorer supports the following InfluxDB 3 products:
 
     - **Server name**: A name to identify the InfluxDB 3 server you're connecting to.
     - **Server URL**: The URL used to connect to your InfluxDB 3 server.
+      - The URL depends on how and where your InfluxDB 3 instance is running. See [When to use `host.docker.internal`](#when-to-use-hostdockerinternal) for more information.
       - Select the protocol to use (http or https).
       - Provide the host and, if necessary, the port.
-        - _If connecting to a local, non-Docker instance, use `host.docker.internal`._ For more information about host.docker.internal, see the [Docker documentation](https://docs.docker.com/desktop/features/networking).
+  
+       > [!Note]
+       > #### When to use `host.docker.internal`
+       >
+       > If your InfluxDB 3 instance is running in Docker (not the same container as Explorer),
+       > use `host.docker.internal` as your server host to allow the Explorer container to
+       > connect to the InfluxDB container on the host--for example:
+       >
+       > ```txt
+       > "DEFAULT_INFLUX_SERVER": "http://host.docker.internal:8181"
+       > ```
+       >
+       > - If both Explorer and InfluxDB are in the same Docker network, use the container name instead.
+       > - If InfluxDB is running natively on your machine (not in Docker), use `localhost`.
+       >
+       > For more information, see the [Docker networking documentation](https://docs.docker.com/desktop/features/networking/#i-want-to-connect-from-a-container-to-a-service-on-the-host).
+
     - **Token**: The authorization token to use to connect to your InfluxDB 3 server.
       We recommend using an InfluxDB 3 _admin_ token.
       
@@ -122,7 +139,7 @@ The Results pane provides three view options:
 > - Ensure that you query the `time` column
 > - Update the query to include an `ORDER BY time` clause.
 
-Congratulations! You have successfully used {{% product-name %}} to connect to,
+You have successfully used {{% product-name %}} to connect to,
 write data to, and query data from an InfluxDB 3 instance.
 
 ## Video walkthrough

content/influxdb3/explorer/install.md

@@ -240,14 +240,20 @@ Instead of configuring connections through the UI, you can pre-define connection
    - **`DEFAULT_SERVER_NAME`**: a display name (only used by Explorer) for your [InfluxDB 3 Core](/influxdb3/core/get-started/setup/#start-influxdb) or [Enterprise](/influxdb3/enterprise/get-started/setup/#start-influxdb) server
 
    > [!Note]
-   > If connecting to a local, _non-Docker_ instance, use `host.docker.internal` as your server host--for example:
+   > #### When to use `host.docker.internal`
+   >
+   > If your InfluxDB 3 instance is running in Docker (not the same container as Explorer),
+   > use `host.docker.internal` as your server host to allow the Explorer container to
+   > connect to the InfluxDB container on the host--for example:
    >
    > ```txt
    > "DEFAULT_INFLUX_SERVER": "http://host.docker.internal:8181"
    > ```
    >
-   > `host.docker.internal` allows the Docker container to connect to services running on your host machine.
-   > For more information, see the [Docker documentation](https://docs.docker.com/desktop/features/networking).
+   > - If both Explorer and InfluxDB are in the same Docker network, use the container name instead.
+   > - If InfluxDB is running natively on your machine (not in Docker), use `localhost`.
+   >
+   > For more information, see the [Docker networking documentation](https://docs.docker.com/desktop/features/networking/#i-want-to-connect-from-a-container-to-a-service-on-the-host).
 
 2. **Mount the configuration directory:**