Not being technical, I'm not sure I understand what is needed.
In case you need a beam with a cross-section in the form of a "+" you could easily use two thin, elongated boxes to create a +-form. Make it light-gray and glossy, and you have a chrome crossbeam.

On page 16-17 there are some cross-shaped columns visible, maybe that's what you need? Same process. On page 20 I count 12 of those. So my guess is, you don't need beams, but columns.

Study how to make a video, and you know how to make your walkthrough.

H