After you have created a program, you will need to download your code onto the micro:bit on your Roversa. Plug the micro:bit into your computer and either pair it (preferred option) or download as file (alternative option).
Note: Be aware that when you start using MakeCode, the buttons on Roversa will no longer function as they do in Standalone Mode. If you want to switch back to Standalone Mode, follow instructions for uploading the firmware onto the micro:bit.