This node enables you to create a two-dimensional data set by manually adding points from a coordinate system: left-click a point to add it and right-click it to remove it. With the "Snap to Grid" option, points are positioned on the intersection of the grid, as configured. The class option allows to you set up a third dimension, which outputs to an integer column.
Use the clear button with caution as it removes all the points from the coordinate system.