If you've built your project and want to share this internally you can follow the steps below.
Step-by-step guide
Log into your admin account
Click on the project you would like to share internally
Click the Share button in the top right corner
Select 'Enable for projects and tools'
You will now have a private link you can share internally with your team while the project is not publicly visible. Share the URL by clicking copy button
You can remove access to this link at any time by disabling the 'Enable for projects and tools' button