To use the Code Editor, you will need to do a little bit of setup in Chrome. This involves setting a couple of flags to enable Web Bluetooth and should be done regardless of your device or OS. There are some basic instructions on the website when you first get there, but the instructions below cover those in a bit more detail.
The flags are mostly required for storing the bond and reconnecting because some of the functions fairly new. The exception is on Linux where the flags are required to connect at all. So if you are on a non-Linux platform and would rather not enable the flags, keep in mind that the connect button will not function and you will need to create a new Bluetooth pairing each time you connect.
In the address bar for Chrome, type chrome://flags and press enter. This will take you to the internal Chrome flags settings. In the search box, type in enable-experimental-web-platform-features and you should see only one result.
Change disabled to enabled.
In the search box, type in enable-web-bluetooth-new-permissions-backend and you should again see only one result. Change the setting to Enabled and click the Relaunch button.
That's it! You should be ready to go.