The data aggregator essentially works by taking all your heatmap data and then snapping each point to a grid. The grid's size is what you define using the aggregation factor. For example, if your aggregation factor is set to 10, it will take all the coordinates in your dataset and snap them to the nearest coordinate evenly divisible by ten. By default, we use an aggregation factor of 5, so any points within a 5 pixel radius of each other are grouped together. This makes very large amounts of data a lot easier to analyse, and often better highlights the more important locations of your page as you increase the aggregation factor. If you set the aggregation factor to 1 you'll see the exact location the mouse was clicked.
The minimum point count eliminates any coordinates being drawn on the heatmap which have less than the number defined. For example, if minimum point count is set to 2, then the heatmap will only draw points with 2 or more hits.