Using Model Builder in ArcGIS Pro on active user selection inputs

[CyndyBresloff]

I'm very rusty with using Model Builder and trying to create a model in ArcGIS Pro 2.3.  What I would like to do, is, after the user (me!) makes a selection by hand on the map, use those inputs (in this case, two points in a hand drawn selection on the map) as input to Model Builder to alter a variable in a table related to one of the points as compared to the other.  My problem is I can't seem to figure out how to get the inputs into Model Builder from an active selection, as this task requires a human eye and can't be automated.  Anyone have some suggestions?

[DuncanHornby]

It's not entirely clear if you want your selection to exist before you run the model or create them during model run. If it is the later explore the help file on the subject of Feature Sets.