updated install docs for arm dev system

Author: jpswinski

docs/rtd/source/developer_guide/how_tos/amazon_linux_arm_setup.md

@@ -113,12 +113,19 @@ pre-commit run --all-files
 
 ### 8. Installing and Configuring Docker
 
+To install docker
 ```bash
 sudo dnf install docker curl
 sudo usermod -aG docker <username>
 newgrp docker
 ```
 
+To start docker
+```bash
+sudo systemctl start docker
+sudo systemctl enable docker
+```
+
 Then install Docker Compose plugin
 ```bash
 DOCKER_CONFIG=${DOCKER_CONFIG:-$HOME/.docker}