Multi SIte project creation

Hello All

I am trying to create a multi-site project setup. I followed the documentation and but stil unable to figure out how to run all site at once? should we run them from parent sub-project ? if yes, how?
Can some one please explain this with sample?

The idea is that you have two separate code bases, one core project and one second site project, so you can run two Tomcats, both with mvn
Add a Second Delivery Webapp - Bloomreach Experience - Headless Digital Experience Platform and sibling pages.

But note that for far most uses case, a single site webapp is best practice, supporting multiple sites (channels).