Where to configure lxd containers?

I installed LXD and created a few containers and while reading about various configurations (specifically about how to run unprivileged containers as root), I saw that the configuration files referenced in the various pages are

• multiple (/etc/lxc/default.conf, /var/lib/lxc/<container>/default, ...)
• and for the most part do not exist on mu Ubuntu 15.10.

It looks like the lxc command is the actual way to go, for instance

# lxc profile show test1
name: test1
config: {}
description: ""
devices:
  eth0:
    name: eth0
    nictype: bridged
    parent: br2
    type: nic

I do not understand how information of the kind

Append to [one of the config files mentioned above]

lxc.id_map = u 0 100000 65536
lxc.id_map = g 0 100000 65536

fits into the lxc command (if at all):

• should I be editing the configuration via lxc profile edit test1 - in which case where (to take the example above) would lxc.id_map = u 0 100000 65536 go in?
• or use something like lxc config set test1 raw.lxc 'lxc.id_map = u 0 100000 65536'? (when tested, it does not appear in the profile after execution)
• or something else?