The measurements on that page are in pixels (@ 96ppi). Not very conveniant.
I think that is for importing into inkscape.
You can do the same from within Inkscape BUT it’s in an obscure place (edit/clone/create tiled clones) AND you will need a tutorial to get the best out of it. eg for an equally spaced grid of 4 x 4 circles, first create your circle then launch create tiled clones, click on the shift tab and enter 4 x 4 in Rows, Columns, then under shift X per column enter 100 and Shift Y per row enter 100 and click create.