From what I've seen and read the install process seems similar to the JCR Roof Rack. The only major difference I see is the JCR sticks a little further forward and has a lower reaching front fairing. JCR didn't come with written instructions either but has a much more complete install video.
Both the Spider and the JCR are very involved to install but certainly are probably unmatched in function of a low profile platform for mounting stuff on your roof
Love the look, hate that you have to drop the headliner to install it. Does the Spider still allow the moonroof to open? The JCR specifically does not.
I bought one, haven't installed it, kind of regret buying it. They released a Part 1 video a year+ ago that showed removing the headliner and prepping the OEM rail removal but then never made a second video to show how to install the actual rack. They have a lot of racks for Toyota/Subaru type vehicles so maybe they just never sold enough for the Bronco Sport and gave up, but that's still not great customer service.