docs: update info about starting frontend dev locally (no docker)

docs/dev/Frontend.md

@@ -30,19 +30,17 @@ For details on how to run the API first, please see:
 
 ## 2. Start the Frontend locally
 
-### 2A: Navigate to the frontend subdirectory
+To run the frontend locally, connected to the staging server as a backend:
 
-`cd src/frontend`
-
-### 2B: Install dependencies
-
-`npm install`
-
-### 2C. Run the project
+```bash
+just --unstable start frontend-dev
+```
 
-Run the frontend with hot-reloading: `npm run dev`
+The mapper frontend can be started with a similar command:
 
-The frontend should now be accessible at: `http://127.0.0.1:<PORT_NUMBER>`
+```bash
+just --unstable start mapper-frontend-dev
+```
 
 ## Frontend Tips