Question: I just installed Odin on an older Windows 8 vintage Dell laptop. I have totally forgotten how to troubleshoot the chipset and get the kernel sources installed correctly. I’ve gotten as far as installing the BCMWL Kernel source package from AppCenter, but I am totally lost.

Answer: 
Have been struggling with this, too. You need to install Kernel Headers first. See this:

<https://github.com/elementary/os/issues/526#issue-965454894>

you might need to
sudo apt-get install --reinstall bcmwl-kernel-source
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