Update README.md

Author: debugger24

README.md

@@ -1,3 +1,19 @@
 # GitHub Action - AWS SSM Run Command
 
 Github Action for running commands on Linux or Windows machine managed using SSM
+
+## Usage
+
+```yaml
+- name: Execute command
+  uses: debugger24/action-aws-ssm-run-command@v1
+  with:
+      aws-region: us-east-1
+      instance-ids: |
+        instance_id_1
+        instance_id_2
+      commands: |
+        pwd
+        ls
+        echo "Executed by Github Actions Workflow #${{ github.run_id }}" >> test.txt
+```