there is no real server side to this, but you do need to serve the code up from either localhost or a site with SSL enabled. if on Mac or Linux, you can start a simple webserver by running: python -m SimpleHTTPServer 8080

Your laptop MUST have BLE support for this to work.

Copy and paste the contents of the microbit.ts file into the https://pxt.microbit.org/ editor to get a .hex