To share a preview of your project please follow these steps:
Navigate to Playground and ensure you're logged in
Upload a playground build or select an existing build
Click the Kebab menu (3 dots) at the end of the row containing the version of you wish to send to your team
Select "Copy preview link"
The URL to preview this version of your playable will now be copied, simply send it to your team and they will be able to play the playable in their browser.