Stl part

You can get this dialog box pressing the 'Cut as Untapered Slices' link located in the 'Cut Sliced Stl Part'

You can use this if you just own a Cnc machine with 2 or 4 linear axes. If you press 'Cut as Untapered Slices' button the following dialog will appear:

Using untapered Slices will probably require more sanding than the Untapered feature, but preparing them is simplest and untapered parts are faster to cut.

Now we will explain in deep every single part of the dialog.

Left side: the parameters and commands

You can see listed here all the Sliced part defined in the previous dialog.
For each item you can see the dz value (the thickness of the foam panel you'll use then) and the z height where the Slice is placed.
You can also switch off parts Unchecking them.
When you go then to export/cut them, you can also select all the Slices with the same thickness of the selected one just by pressing the 'Check all Parts with the same dz of the selected one' button.

Section interpolation type: every slice can be internally computed splitting in in sub-slices, and using then the Union of all the XY sections as shape of the final Sliced part.
You can select among None/Light/Medium/Best where None doesn't apply subinterpolation and Best uses the more accurate interpolation.
This parameter can help you when some slice have internal sections larger than the upper/lower section, to avoid to cut a too little sliced part.

Added Offset to Contours: value. Applying a non zero value here you can create larger sections, so you have more material available when then you go to the final sanding job.

Apply Markers to help Alignment, size = value. You can apply round extruded marks of the selected size to the Sliced parts contour. This will help you to align the parts when assembling them.

Reference Holes to Help Parts aligment. Using this Frame you can apply 4 Reference holes, to help you to align the parts when assembling them. For each Reference hole you can setup the size, the position and if you want to apply it. Press then the below 'Apply' button to apply these settings.
Using this feature you can then use some 'spars' as a Reference to align the sliced parts in a proper and accurate way.

Apply: the above settings will be applied.

Cut: the 'Advanced Cutting Wizard' will appear, with all the Checked Sliced parts already included. In this way you can in a short time nest and cut them using your Cnc Foam cutting machine.

Save to .DC1: a filename will be prompted and all the Checked Sliced parts will be included there. In this way you can further refine them, if required.

In the 2D preview you will see the geometry of the actual sliced element as a XY section.
You can navigate the sections by selecting a different item in the Sliced parts list, or just moving the vertical cursor placed at the left side of the 2D preview.

Pressing the 'Fit to screen' button you will maximize the drawing to the 2D preview window size.

You can see here the 3D Preview of the Stl part (optional) and all the checked Sliced parts
The actual Sliced part will be rendered as Red.
If you have the STL part enabled and you see some part of it out of the Sliced part, you can increase the Section interpolation type or Apply a larger Added Offset to Contours value.