Add milling objects

Here you select the milling tool you want to use, a smaller tool

gives better results but generates more vectors, so you may have

to experiment a bit here with different tool sizes.

Now select horizontal or vertical. Because rub-out generates a lot of traces, it's best to select the direction in which the longest lines could be generated.

Now place the mouse in the center of the area you would place the object.

Hold the left mouse down and move the mouse, on release your object is created.