Update README.md (#32)

README.md

@@ -25,7 +25,6 @@ on different operating systems:
 | Windows                   | (:heavy_check_mark:)     | TODO                                 |
 | MacOS                     | TODO (I dont own a Mac)  | TODO (I dont own a Mac)              |
 
-
 ## Build and Run
 Build in release mode:
 ```sh
@@ -56,6 +55,30 @@ an executable with just support for wayland:
 cargo build --no-default-features --features wayland
 ```
 
+## Usage
+### Gtk Frontend
+By default the gtk frontend will open when running `lan-mouse`.
+
+To add a new connection, simply click the `Add` button on *both* devices,
+enter the corresponding hostname and activate it.
+
+If the mouse does can not be moved onto a device, make sure you have port `4242` (or the one selected)
+opened up in your firewall.
+
+The cli interface can be enabled using `--frontend cli` as commandline arguments.
+Type `help` to list the available commands.
+
+E.g.:
+```
+$ cargo run --release -- --frontend cli
+(...)
+> connect <host> left|right|top|bottom
+(...)
+> list
+(...)
+> activate 0
+```
+
 ## Configuration
 To automatically load clients on startup, the file `config.toml` is parsed.
 (must be in the directory where lan-mouse is executed).