Game servers here are managed, so there is no SSH or shell access to them. Commands such as chmod, chown or sudo cannot be run against your server, and they are never needed.
File permissions are handled for you. A permission-looking error in the console is not something you can fix by changing permissions, so please open a ticket instead of trying to.
To work with your files you have two options:
The Files page in the Panel, for browsing and editing.
SFTP for large uploads — your address and username are on the Settings tab, and you connect with your panel password.
The Console is the game's own console, not a Linux terminal — it accepts the game's commands only.
If you need help with this, please submit a ticket.