Create your iDev Games account
- Export -f GAME_NAME.html
- Zip the newly created folder
- Upload your game to your iDev Games account
If you want some help exporting your Pico-8 game then check out the Pico-8 manual (lexaloffle.com/dl/docs/pico-8) under section 3.
If you want some help zipping your HTML files then check out this tutorial here (play.idevgames.co.uk/post/how-to-pr).
To upload your game you need to log in to your account and click on the upload game link (play.idevgames.co.uk/upload-your-ga) and follow the instructions there.