Here’s what the Flux documentation says about modifying the PCB board outline shape and dimensions:

"In this tutorial, we'll explore the different ways to create and modify board outlines in Flux, allowing you to customize your PCB shape and size to fit your project requirements.

The board outline defines the physical boundaries of your PCB and is one of the first design decisions you'll make. Flux provides several options for creating board outlines, from simple shapes to complex custom designs.

We'll cover the following topics:

Basic Shapes

Flux has built-in support for simple shapes (circular and rectangular). For complex shapes, please refer to the section on Advanced (custom) shapes.

Changing the Outline Shape" Source

If you need more detail from that page, let me know which outline type (rectangular, circular, or custom import) you’re targeting and I can pull the specific section.

how do i add railing

I couldn’t find any Flux documentation about “railing.” This likely means there’s no documented feature by that name.

Which of these did you mean?

Tell me which one and I’ll pull the exact steps from the docs.