I have a model that I will use to publish as a geoprocessing service. I first select two objects from a database and create a new datalayer from that selection. I now want to allow a user, online, to pick one of four values to add to a particular attribute of that new datalayer in order for the second tool to run. Right now I have added "Calculate Field" with the mathematical equation hard coded for one of the four values. And the model runs perfectly with that, however I can't seem to find the way to allow a user to change it. I thought "Create Variable" = "Long" as an input might do it but I don't know how to connect that Variable to the Calculate Field tool.