Plotting a point
On a 10 mm unit grid, the pair (2, 3) is two units right of the origin and three units up—about 20 mm right and 30 mm up. (−1, −2) is one unit left and two units down. With 5 mm units the same pair occupies half those millimetre distances.
Article: how to print a coordinate plane. Presets: numbered, unnumbered, and major-line planes.