Enhances Docker Set up documentation

Author: ndegwamartin

docker/README.md

@@ -30,7 +30,7 @@ To load this dataset into the HAPI FHIR image, do the following:
      -O fhir.zip
    ```
 
-3. Unzip the file, a directory named `fhir` should be created containig JSON
+3. Unzip the file, a directory named `fhir` should be created containing JSON
    files:
 
    ```
@@ -42,6 +42,10 @@ To load this dataset into the HAPI FHIR image, do the following:
    repo to upload the files into the HAPI FHIR container
    `docker run -it --network=host \ -e SINK_TYPE="HAPI" \ -e FHIR_ENDPOINT=http://localhost:8080/fhir \ -e INPUT_DIR="/workspace/output/fhir" \ -e CORES="--cores 1" \ -v $(pwd)/fhir:/workspace/output/fhir \ us-docker.pkg.dev/cloud-build-fhir/fhir-analytics/synthea-uploader:latest`
 
+   _Note:_ The `$(pwd)/fhir` part of the command mounts the local `fhir`
+   directory (created in step 3) into the container at `/workspace/output/fhir`,
+   which is where the uploader expects to find the files.
+
 5. As the uploader uses `POST` to upload the JSON files, the server will create
    the ID used to refer to resources. We would like to upload a patient list
    example, but to do so, we need to fetch the IDs from the server. To do so,