Update Readme

README.md

@@ -8,6 +8,8 @@ Official [Meshtastic](https://meshtastic.org) web interface, that can be run ind
 
 ## Development & Building
 
+### Building and Packaging
+
 Build the project:
 
 ```bash
@@ -19,3 +21,29 @@ GZip the output:
 ```bash
 pnpm package
 ```
+
+### Development
+
+Create a `.env` file:
+
+```bash
+cp ./.env.example ./.env
+```
+
+And define the device IP address in the `.env` file.
+
+```
+SNOWPACK_PUBLIC_DEVICE_IP=xxx.xxx.xxx.xxx
+```
+
+Install the dependencies.
+
+```bash
+pnpm i
+```
+
+Start the developtment server:
+
+```bash
+pnpm start
+```