Users can upload their solutions directly from bit based source control(Github/Bitbucket) to Playground. This option requires a public URL of your repo to set up a play, so this means your repository should be open. The user needs to make sure that the Repo follows the same structure as that or Salesforce.
Click on the Add Play button, which is the location at the top right of the screen.
This will open a popup with selection for the importing method. Let us choose Public Repo and enter the git URL of the repository.
Enter a valid and meaningful name for the play and click on Continue.