render a grid layout and to each corner of grid

[Ofnuts]

For the dots, just use a pattern fill:

- Make an image with dimensions equal to the horizontal and vertical distance between the dots.
- Make the background layer transparent (or replace with transparent layer)
- Add a dot in it
- Select/All, copy to clipboard
- In the chart image, select the "clipboard" pattern (first one)
- Bucket-fill a new layer with the pattern

You may have to do a couple of tries to figure out where the dot should be in the first image so that it shows where you want on the chart.

For the larger grid: Filters>Render>Pattern>Grid