The easiest way to use this is by using the =GetKMeansCluster() formula in a table.
For something that will probably calculate quicker, you can use =GenerateAllClusters() and then add those in order with a column formula like =Clusters.Nth(Points.Find(thisRow))
Note that the name of the clusters will differ based on randomness even with the same inputs, but the centroids should be about the same.
I also wrapped clustering of 1 to provide a centroid formula. The centroid of the points above is: ()