Merge pull request #15467 from craig-osterhout/hub-quickstart-pull

[ENGDOCS-829] Add pull image to hub quickstart

docker-hub/index.md

@@ -125,14 +125,53 @@ To create a repository:
 
 ### Step 3: Download and install Docker Desktop
 
-We'll need to download Docker Desktop to build and push a container image to
-Docker Hub.
+You'll need to download Docker Desktop to build, push, and pull container images.
 
 1. Download and install [Docker Desktop](../desktop/#download-and-install).
 
 2. Sign in to the Docker Desktop application using the Docker ID you've just created.
 
-### Step 4: Build and push a container image to Docker Hub from your computer
+### Step 4: Pull and run a container image from Docker Hub
+
+1. Run `docker pull hello-world` to pull the image from Docker Hub. You should see output similar to:
+
+   ```console
+   $ docker pull hello-world
+   Using default tag: latest
+   latest: Pulling from library/hello-world
+   2db29710123e: Pull complete
+   Digest:   sha256:7d246653d0511db2a6b2e0436cfd0e52ac8c066000264b3ce63331ac66dca625
+   Status: Downloaded newer image for hello-world:latest
+   docker.io/library/hello-world:latest
+   ```
+
+2. Run `docker run hello-world` to run the image locally. You should see output similar to:
+
+    ```console
+    $ docker run hello-world
+    Hello from Docker!
+    This message shows that your installation appears to be working correctly.
+
+    To generate this message, Docker took the following steps:
+     1. The Docker client contacted the Docker daemon.
+     2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
+     (amd64)
+     3. The Docker daemon created a new container from that image which runs the
+     executable that produces the output you are currently reading.
+     4. The Docker daemon streamed that output to the Docker client, which sent
+     it to your terminal.
+
+    To try something more ambitious, you can run an Ubuntu container with:
+     $ docker run -it ubuntu bash
+
+    Share images, automate workflows, and more with a free Docker ID:
+     https://hub.docker.com/
+
+    For more examples and ideas, visit:
+     https://docs.docker.com/get-started/
+    ```
+
+### Step 5: Build and push a container image to Docker Hub from your computer
 
 1. Start by creating a [Dockerfile](../engine/reference/builder/) to specify your application as shown below:
 
@@ -164,7 +203,8 @@ Congratulations! You've successfully:
 
 - Signed up for a Docker account
 - Created your first repository
-- Built a Docker container image on your computer
+- Pulled an existing container image from Docker Hub
+- Built your own container image on your computer
 - Pushed it successfully to Docker Hub
 
 ### Next steps