NAM 2018 is not generally available yet. We are still in beta, actually at the end of this phase. Release Candidate has been made available to the beta users, on 7/16. This should be the last update before GA in September. If you are the beta program participant, RC builds would be available for you for download. If you are not the beta program participant - please sign up and we will make the RC build available for you.
Thanks All : Kris,Babar & Rastislav for you quick support here! we have DCRUM 2017 SP5 running in Prod environment but there is no dev setup to test Beta.
We are waiting for GA release so that we can upgrade in production environment.