[docs] Update section on installing packages.

Update and clarify the section on updating and installing packages in
packages.md. This also replaces all instances of amberctl with
equivalents of pkgctl in the docs.

Fixed: 74321
Change-Id: Ib7b9d8aa5402475b9d5b423ea33522a2fcd637a2
Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/514380
Reviewed-by: Erick Tryzelaar <etryzelaar@google.com>
Commit-Queue: Thomas Zander <thomasalpinus@google.com>
diff --git a/docs/development/idk/documentation/packages.md b/docs/development/idk/documentation/packages.md
index a99c29c..184ad06 100644
--- a/docs/development/idk/documentation/packages.md
+++ b/docs/development/idk/documentation/packages.md
@@ -132,14 +132,30 @@
    By default, this starts an amber server on the host machine at port `8083`.
 
 2. (On the target device) Add the new repository as an update source with
-   `amberctl`:
+   `pkgctl`:
 
    ```
-   amberctl add_repo_cfg -n $REPO -f http://$HOST_ADDRESS:8083/config.json
+   pkgctl repo add url -f 1 -n $REPO http://$HOST_ADDRESS:8083/config.json
    ```
 
-   If the component is not already on the system, `amberctl` installs the package.
-   If the package already exists, `amberctl` installs any package updates.
+   The option `-f 1` must be set if `pm` is serving a component v1 config.json
+   configuration file. (This is currently the case, but will change to serving
+   component v2 configuration files in the future. Once this change has
+   happened, the `-f 1` can be omitted.)
+
+   Providing a short name for the repository using `-n $REPO` is optional, but
+   helpful. If this short name is not provided, `pkgctl` will derive it from
+   the provided config URL.
+
+3. Get the package:
+
+   ```
+   pkgctl resolve fuchsia-pkg://$REPO/$PACKAGE_NAME
+   ```
+
+   If the component is not already present on the system, `pkgctl` downloads the
+   package and places the blobs in the blobfs in the process of resolving. If
+   the package already exists, the updates will be downloaded.
 
 You have successfully installed or updated the package. You are now ready to
 run a component from the installed package.