docs: add installing plugins from a compiled binary example

website/content/docs/plugins/creation/index.mdx

@@ -248,16 +248,31 @@ scope of a plugin.
 
 ### Testing Plugins
 
-Making your unpublished plugin available to Packer is possible by either:
+To install plugins from local source, you can use the `packer plugins install` command with the `--path` flag:
 
-- Starting Packer from the directory where the plugin binary is located.
-- Putting the plugin binary in the same directory as Packer.
+```shell-session
+$ packer plugins install --path <path-to-binary> <hostname>/<namespace>/<plugin-name>
+```
 
-In both these cases, if the binary is called `packer-plugin-myawesomecloud` and
-defines an `ebs` builder then you will be able to use an `myawesomecloud-ebs`
-builder or source without needing to have a `required_plugin` block.
+For example let's install happycloud plugin from a locally sourced binary
 
-This is extremely useful during development.
+```shell-session
+$ packer plugins install --path packer-plugin-happycloud github.com/hashicorp/happycloud
+```
+
+This will install the happycloud plugin from the `packer-plugin-happycloud` binary so Packer can discover it.
+If you want to use this in an HCL2 template, you can optionally add it to the `required_plugins` section like so:
+
+```hcl
+  required_plugins {
+    happycloud = {
+      source = "github.com/hashicorp/happycloud"
+      version = ">=0.0.1"
+  }
+}
+```
+
+For further information on how Packer discovers and loads plugins, you may refer to our [documentation](/packer/docs/plugins/creation/plugin-load-spec) on the subject.
 
 ### Distributing Plugins