The controller cannot connect over Bluetooth. What should I check?

The Web Bluetooth API is only supported in Chrome / Edge (desktop and Android), and the site must be opened over HTTPS. Check your browser version and make sure the address starts with https://.

Do I need to install any software?

Not for Stage 1 — just open the controller in a browser. From Stage 2 onwards you may need the SDK depending on the lesson; see Downloads.

Is this site free?

Yes. The courseware and the Web BLE controller are both free to use.