I'm trying to make files in my linux virtual server browsable from my windows. I'm following the instructions given here: https://help.ubuntu.com/lts/serverguide/samba-fileserver.html
However, I cannot find the security parameter it's talking about. Can I just create that anywhere under the [global]? Or is there a pretty specific place to put it?
Yep, you can just specify the "security=" parameter anywhere in the global section. https://www.samba.org/samba/docs/man/manpages/smb.conf.5.html