First of all, I may recommend you to read this complex guide - how to install a complex Mirantis OpenStack Environment on Virtualbox - https://docs.mirantis.com/openstack/f...

In brief: If you have already launched your environment using automated scripts, there 3 or 5 (or other custom amount) nodes have to be launched. You may create a new environment, there you may add new nodes that have been already launched via PXE, and assign them some roles (controller, compute and storage at least) - after that you may easily deploy your environment.

If you have some specific issues, you may follow the guide via the link, posted above and follow the troubleshooting recommendations. Otherwise, you may ask your question here, but provide us with detailed description of an issue and/or screenshots.

Have a good luck!