What are the steps to add Network Analyst functionality to a AGO map? I have a network data set published as a service and have added it to AGO. I've read that Network functions are now avail in AGO, but can not find any info on how to enable maps in AGO to be able to solve routing tasks.
Not sure you will be able to do this in AGOL with your own network datasets. However, you might take advantage of hosted by Esri routing services.
More info on Network Analysis Services.