Windows 11 is updated to Moment 2 completely automatically, via Windows Update, on PCs that have already been updated to Windows 11 22H2, that is, which have installed the second half-yearly update of 2022.
Those in a hurry to try Moment 2, however, can go to Settings> Windows Update and look for updates waiting to be downloaded and/or installed. Otherwise, just wait a few days: Moment 2 is already in rollout.