docs: Add setup instructions for linux AppImage package

docs/content/setup/linux.md

@@ -11,4 +11,70 @@ tags: ["setup", "AppImage", "linux"]
 
 ## Deployment
 
+1. Make the AppImage package executable:
+    ```bash
+    chmod u+x Infection_Monkey_v1.11.0.AppImage
+    ```
+1. Start Monkey Island by running the Infection Monkey AppImage package:
+    ```bash
+    ./Infection_Monkey_v1.11.0.AppImage
+    ```
+1. Access the Monkey Island web UI by pointing your browser at
+   `https://localhost:5000`.
+
+### Start Monkey Island with user-provided certificate
+
+By default, Infection Monkey comes with a [self-signed SSL
+certificate](https://aboutssl.org/what-is-self-sign-certificate/). In
+enterprise or other security-sensitive environments, it is recommended that the
+user provide Infection Monkey with a certificate that has been signed by a
+private certificate authority.
+
+1. Run the Infection Monkey AppImage package with the `--setup-only` flag to
+   populate the `$HOME/.monkey_island` directory with a default
+   `server_config.json` file.
+
+    ```bash
+    ./Infection_Monkey_v1.11.0.AppImage --setup-only
+    ```
+
+1. (Optional but recommended) Move your `.crt` and `.key` files to
+   `$HOME/.monkey_island`.
+
+1. Make sure that your `.crt` and `.key` files are read-only and readable only
+   by you.
+
+    ```bash
+    chmod 400 $HOME/.monkey_island/{*.key,*.crt}
+    ```
+
+1.  Edit `$HOME/.monkey_island/server_config.json` to configure Monkey Island
+    to use your certificate. Your config should look something like this:
+
+    ```json {linenos=inline,hl_lines=["11-14"]}
+    {
+      "data_dir": "~/.monkey_island",
+      "log_level": "DEBUG",
+      "environment": {
+        "server_config": "password",
+        "deployment": "linux"
+      },
+      "mongodb": {
+        "start_mongodb": true
+     },
+      "ssl_certificate": {
+        "ssl_certificate_file": "<PATH_TO_CRT_FILE>",
+        "ssl_certificate_key_file": "<PATH_TO_KEY_FILE>",
+      }
+    }
+    ```
+
+1. Start Monkey Island by running the Infection Monkey AppImage package:
+    ```bash
+    ./Infection_Monkey_v1.11.0.AppImage
+    ```
+
+1. Access the Monkey Island web UI by pointing your browser at
+   `https://localhost:5000`.
+
 ## Upgrading