How to create heat map of points with fishnet or tessellation?

[MikeAdam]

I have started using ArcMap 10.6 and need to create a heat map of point counts over the country. I am able to draw the fishnet over a smaller test area. What tool do I need to use to fill in the fishnet squares with graduated colors of point counts? I have tried numerous examples from google but they have not worked. My data set consists of only Lat/Long pairs in a file. I have converted these to shape files. 

I attached a small screen cap of what I am trying.

[DanPatterson_Retired]

Pro has some nice features, but try joining the tessalation to the points...

Did you try a spacial join?

http://desktop.arcgis.com/en/arcmap/latest/tools/analysis-toolbox/spatial-join.htm

you have a many to one relationship which you want the join count values for the polygons

[SteveLynch]

what about Density?

[DanPatterson_Retired]

If you have the spatial analyst extension and the tessalation is converted to raster first so you can control cell size, and analysis extent and related parameters.

[MikeAdam]

I don't have the pro version. But I do have the spatial analysis add on.

But I need more basic help on this one. I created a tessellation over the whole country (USA). It is very slow. 

I used a simple join from tessellation to the longitude field to test out and I can see highlighted hexagrams if I also apply a "Select by Attribute" on the Join shape file. But this is not what I am interested in. 

Is there any website/video that can help get me understand steps to get a point count heat map? 

Also I have tried PointDensity and Aggregation and these dont seem to take the tessellation as an input field. Also PointDensity has very odd distributions such as -1,307,732.125 -- -1,162,428.556... I know at least the coord projections are the same.