If you want to access the environment using external SSH then you have to add the private key to the cloud environment . you can do that using the following steps
Go to Setting on the top of the dashboard
Within the opened User Settings tab, switch to the SSH Keys > Private Keys option and click on the Add Private Key button.
Copy your private SSH key and paste it into the Key text field. Then type a Name for this key (e.g. git-key) and finish the addition with the Add button.