At the GridEditor node are two pins called “Control U” & “Control V”, where you need to specify the number of control points.
Press “restart” and the new grid is created - also according to the spacings you specified. For example if you have “Control U” is 12 you may specify 11 spacings inbetween them. The new grid will we created accordingly each time you press restart.
Note that there is no possibility to add points on an already edited grid. You need to think about the needed points and spacings first and then work with this grid architecture.