That's a good point. I've added to the post. It's simple enough I'd expect anyone who wants to do it can follow the docs from CADO-NFS, which are very good, but I can write it down explicitly.

Install CADO-NFS per upstream directions.

Get the number you want to factor. I just did this in a python repl, something like:

    from cryptography import x509
    f = open("gold-server.pem", "rb").read()
    print(x509.load_pem_x509_certificate(f).public_key().public_numbers().n)

That gets you the `n` to factor - The big number below.

Then pass it to CADO-NFS. The full invocation for the server root was:

    ./cado-nfs.py 10754123440737946604182274398563307850262685121187325065132187145895199633213947273310647001521000121802425390193123548314361970563322281259804690831526167 -t 32 --workdir /data/cert1

All run in a tmux to keep it alive for the few days, of course.