Each of the projects (Loom, Panama, Valhalla, Amber, etc.) are in different stages and are intended to deliver features over time. Project Loom itself is not a single deliverable. As mentioned, you can get an early-access build of most of the work that has gone into it so far [1]. The build is based off an incomplete JDK 16 as of this comment. JDK 15 does have one JEP that is part of the path towards Loom [2].