On first start install the npm dependencies:

npm install

Set the BACKEND_URL in .env to your project's url:

# .env
BACKEND_URL=https://REPLACE ME.di1337.com

After this you can start the web server and esbuild watcher:

npm run start

The application server will not display type errors by default. For that you need to start a second process:

npm run typecheck

Before the first type check, open the Project Settings and install the provided TypeScript type declaration for your project.

export BACKEND_URL="https://REPLACE ME.di1337.com"
npm run build