Building Lucee 5 from source

I wanted to see about building Lucee 5.1 form source to try out some of the
newer things I’ve noticed being deployed from JIRA.

I’ve never done this before and followed the guide at docs.lucee.org but I
think that’s referring to the Lucee 4.x repository.

I have Ant set up. What do I need to do for Lucee 5?

Thanks!