The following are all excellent Resources for Information Configuration, Use and Management of LXD Containers !
Simos Xenitellis has a terrific website with many great Guides related to LXD: https://blog.simos.info/
The Official LXD Documentation: https://lxd.readthedocs.io/en/latest/
The LXD User's Forum where developers and experienced LXD experts answer questions daily.
The LXD Sub-Reddit: https://www.reddit.com/r/LXD/
The LXD Project lead, Stephane Graber, has an extensive group of posts about LXD on his own website: https://stgraber.org/
Stephane Graber had also previously published an extensive 12 Part series on LXD which while a couple years old now still has a wealth of great information.