Once you have a datastore, you’re going to want to create at least one dataset. Datasets are versioned collections of data in some datastore. The Azure ML model is quite file-centric, and this concept makes the most sense with something like a data lake, where we have different extracts of data over different timeframes. Perhaps we get an extract of customer behavior up to the year 2018, and then the next year we get customer behavior up to 2019, and so on. The idea here is that you can use the latest training data for your models, but if you want to see how current models would have stacked up against older data, the opportunity is there.
Once you have data and compute, the world is your oyster. Or something like that.